diff --git a/packages/api/test/e2e/promise-alex.spec.js b/packages/api/test/e2e/promise-alex.spec.js
index d2ebf11688..b2a2cbcb10 100644
--- a/packages/api/test/e2e/promise-alex.spec.js
+++ b/packages/api/test/e2e/promise-alex.spec.js
@@ -8,48 +8,97 @@ import WsProvider from '../../../rpc-provider/src/ws';
 describe.skip('alex queries', () => {
   let api;
 
-  beforeAll(async () => {
-    api = await Api.create({
-      provider: new WsProvider('wss://poc3-rpc.polkadot.io/')
-    });
-
-    return api;
-  });
-
   beforeEach(() => {
     jest.setTimeout(3000000);
   });
 
-  it('retrieves the list of validators', (done) => {
-    api.query.staking.validators((res) => {
-      console.log('api.query.staking.validators():', res.toJSON());
+  describe.skip('Remote RPC queries', () => {
+    beforeAll(async () => {
+      api = await Api.create({
+        provider: new WsProvider('wss://poc3-rpc.polkadot.io/')
+      });
 
-      done();
+      return api;
+    });
+
+    it('retrieves the list of validators', (done) => {
+      api.query.staking.validators((res) => {
+        console.log('api.query.staking.validators():', res.toJSON());
+
+        done();
+      });
+    });
+
+    it('retrieves a single value', (done) => {
+      api.query.staking.validators('5EF7wdkP9XZq38fu2ioAvxoEhHUJUc1E2KbuSQSMGofRKhCL', (res) => {
+        console.log('api.query.staking.validators(id):', res.toJSON());
+
+        done();
+      });
+    });
+
+    it('derives a list of the controllers', (done) => {
+      api.derive.staking.controllers((res) => {
+        console.log('api.derive.staking.controllers:', JSON.stringify(res));
+
+        done();
+      });
+    });
+
+    it.skip('retrieves the list of nominators', (done) => {
+      let count = 0;
+      api.query.staking.nominators((res) => {
+        console.log(`[${++count}]:: nominators(${res[0].length}):`, res.toJSON());
+
+        // done();
+      });
     });
   });
 
-  it('retrieves a single value', (done) => {
-    api.query.staking.validators('5EF7wdkP9XZq38fu2ioAvxoEhHUJUc1E2KbuSQSMGofRKhCL', (res) => {
-      console.log('api.query.staking.validators(id):', res.toJSON());
+  describe.skip('Local archive queries (for debug)', () => {
+    beforeAll(async () => {
+      api = await Api.create();
+
+      return api;
+    });
+
+    // https://github.com/polkadot-js/api/issues/845
+    it('retrieves block with no issues', async () => {
+      const metadata = await api.rpc.state.getMetadata('0x6f6f9bba0eed8e3ae9446c37eee763f93118b52a315a7b46090453ba6288da1f');
+
+      console.error(JSON.stringify(metadata, null, 2));
+
+      const block = await api.rpc.chain.getBlock('0x6f6f9bba0eed8e3ae9446c37eee763f93118b52a315a7b46090453ba6288da1f')
+
+      console.error(block);
+
+      expect(block).toBeDefined();
+
+      return true;
+    });
+
+    // https://github.com/polkadot-js/api/issues/846
+    it('handles toJSON with no issues', async (done) => {
+      const signedBlock = await api.rpc.chain.getBlock('0x85c62b581f38cb81c3e443d34392672beb1fb877017fd7237cc87704113259dc');
+      const failed = signedBlock.block.extrinsics.filter((extrinsic) => {
+        try {
+          const json = extrinsic.method.toJSON();
+
+          console.error(json);
+
+          return false;
+        } catch (error) {
+          console.log(extrinsic.method);
+          console.log(extrinsic.method.keys());
+          console.error(error);
+
+          return true;
+        }
+      });
+
+      expect(failed).toHaveLength(0);
 
       done();
     });
   });
-
-  it('derives a list of the controllers', (done) => {
-    api.derive.staking.controllers((res) => {
-      console.log('api.derive.staking.controllers:', JSON.stringify(res));
-
-      done();
-    });
-  });
-
-  it.skip('retrieves the list of nominators', (done) => {
-    let count = 0;
-    api.query.staking.nominators((res) => {
-      console.log(`[${++count}]:: nominators(${res[0].length}):`, res.toJSON());
-
-      // done();
-    });
-  });
 });
diff --git a/packages/types/src/codec/Struct.ts b/packages/types/src/codec/Struct.ts
index 15164e6c30..d05e6e2213 100644
--- a/packages/types/src/codec/Struct.ts
+++ b/packages/types/src/codec/Struct.ts
@@ -2,7 +2,7 @@
 // This software may be modified and distributed under the terms
 // of the Apache-2.0 license. See the LICENSE file for details.
 
-import { hexToU8a, isHex, isObject, isU8a, u8aConcat, u8aToHex } from '@plugnet/util';
+import { hexToU8a, isHex, isObject, isU8a, isUndefined, u8aConcat, u8aToHex } from '@plugnet/util';
 
 import { Codec, Constructor, ConstructorDef } from '../types';
 import { compareMap, decodeU8a } from './utils';
@@ -79,6 +79,7 @@ export default class Struct<
       return Object.keys(Types).reduce((raw: T, key: keyof S, index) => {
         // TS2322: Type 'Codec' is not assignable to type 'T[keyof S]'.
         (raw as any)[key] = values[index];
+
         return raw;
       }, {} as T);
     } else if (!value) {
@@ -99,23 +100,29 @@ export default class Struct<
       // Types, result or any other maps, it's camelCase
       const jsonKey = (jsonMap.get(key as any) && !value[key]) ? jsonMap.get(key as any) : key;
 
-      if (Array.isArray(value)) {
-        raw[key] = value[index] instanceof Types[key]
-          ? value[index]
-          : new Types[key](value[index]);
-      } else if (value instanceof Map) {
-        const mapped = value.get(jsonKey);
+      try {
+        if (Array.isArray(value)) {
+          raw[key] = value[index] instanceof Types[key]
+            ? value[index]
+            : new Types[key](value[index]);
+        } else if (value instanceof Map) {
+          const mapped = value.get(jsonKey);
 
-        // TS2322: Type 'Codec' is not assignable to type 'T[keyof S]'.
-        (raw as any)[key] = mapped instanceof Types[key]
-          ? mapped
-          : new Types[key](mapped);
-      } else if (isObject(value)) {
-        raw[key] = value[jsonKey as string] instanceof Types[key]
-          ? value[jsonKey as string]
-          : new Types[key](value[jsonKey as string]);
-      } else {
-        throw new Error(`Struct: cannot decode type ${Types[key].name} with value ${JSON.stringify(value)}`);
+          // TS2322: Type 'Codec' is not assignable to type 'T[keyof S]'.
+          (raw as any)[key] = mapped instanceof Types[key]
+            ? mapped
+            : new Types[key](mapped);
+        } else if (isObject(value)) {
+          raw[key] = value[jsonKey as string] instanceof Types[key]
+            ? value[jsonKey as string]
+            : new Types[key](value[jsonKey as string]);
+        } else {
+          throw new Error(`Struct: cannot decode type ${Types[key].name} with value ${JSON.stringify(value)}`);
+        }
+      } catch (error) {
+        console.error(`Unable to decode Struct on key '${jsonKey}': ${error.message}`);
+
+        throw error;
       }
 
       return raw;
@@ -130,6 +137,11 @@ export default class Struct<
         super(Types, value, jsonMap);
 
         (Object.keys(Types) as Array<keyof S>).forEach((key) => {
+          // do not clobber existing properties on the object
+          if (!isUndefined((this as any)[key])) {
+            return;
+          }
+
           Object.defineProperty(this, key, {
             enumerable: true,
             get: () => this.get(key)
@@ -212,8 +224,8 @@ export default class Struct<
   toJSON (): any {
     return [...this.keys()].reduce((json, key) => {
       const jsonKey = this._jsonMap.get(key) || key;
-
       const value = this.get(key);
+
       json[jsonKey] = value && value.toJSON();
 
       return json;
diff --git a/packages/types/src/codec/Tuple.ts b/packages/types/src/codec/Tuple.ts
index b2af140e30..f7e880da42 100644
--- a/packages/types/src/codec/Tuple.ts
+++ b/packages/types/src/codec/Tuple.ts
@@ -41,7 +41,13 @@ export default class Tuple extends AbstractArray<Codec> {
       : Object.values(_Types);
 
     return Types.map((Type, index) => {
-      return new Type(value && value[index]);
+      try {
+        return new Type(value && value[index]);
+      } catch (error) {
+        console.error(`Unable to decode Tuple on index ${index}`, error.message);
+
+        throw error;
+      }
     });
   }
 
diff --git a/packages/types/src/codec/Vector.ts b/packages/types/src/codec/Vector.ts
index 4629fb587e..6c341bde4f 100644
--- a/packages/types/src/codec/Vector.ts
+++ b/packages/types/src/codec/Vector.ts
@@ -29,11 +29,17 @@ export default class Vector<T extends Codec> extends AbstractArray<T> {
 
   static decodeVector<T extends Codec> (Type: Constructor<T>, value: Vector<any> | Uint8Array | string | Array<any>): Array<T> {
     if (Array.isArray(value)) {
-      return value.map((entry) =>
-        entry instanceof Type
-          ? entry
-          : new Type(entry)
-      );
+      return value.map((entry, index) => {
+        try {
+          return entry instanceof Type
+            ? entry
+            : new Type(entry);
+        } catch (error) {
+          console.error(`Unable to decode Vector on index ${index}`, error.message);
+
+          throw error;
+        }
+      });
     }
 
     const u8a = u8aToU8a(value);
diff --git a/packages/types/src/codec/utils/decodeU8a.ts b/packages/types/src/codec/utils/decodeU8a.ts
index 50e8629f87..bcb978f598 100644
--- a/packages/types/src/codec/utils/decodeU8a.ts
+++ b/packages/types/src/codec/utils/decodeU8a.ts
@@ -21,7 +21,14 @@ export default function decodeU8a (u8a: Uint8Array, _types: Constructor[] | { [i
   }
 
   const Type = types[0];
-  const value = new Type(u8a);
 
-  return [value].concat(decodeU8a(u8a.subarray(value.encodedLength), types.slice(1)));
+  try {
+    const value = new Type(u8a);
+
+    return [value].concat(decodeU8a(u8a.subarray(value.encodedLength), types.slice(1)));
+  } catch (error) {
+    console.error(`Unable to decode Uint8Array for type '${Type.name}': ${error.message}`);
+
+    throw error;
+  }
 }