NEAR does not produce a block at every height, and 218,363,444 was one it skipped. The backfill asked for its shard layout at the batch's first height, got UNKNOWN_BLOCK from every endpoint, and asked the same question every 15 s from then on: production's indexed_from stopped at 218,363,445. The tip side runs the same code and would have frozen the first time a batch began on a skip. The layout now comes from the first height in the batch that exists. The second half of it: neard sends JSON-RPC errors with HTTP 422 where FastNEAR's proxy sent them with 200, and call_one checked the status before reading the body, so the node's own "no such block" arrived as a transport failure. chunk() could not see a skip as a skip, deep() never asked the archive, and on a chain with several endpoints a node's valid answer would have been failed over. parse_response reads the body whatever the status: a JSON-RPC error is the node answering; a non-success status without one is the host not answering, as before. Checked against near.internal with the scan seeded to begin a backfill batch on the skipped height: it walked past it with no warnings. Closes #31 Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com> Claude-Session: https://claude.ai/code/session_015pkwBsR54NRmZyU4QVhvfj