Cloudflare oddity

The `cloudflare` node actually reports `d61d45` as block `11337655`, but the number for `d61d45` is `11337656` -- the block after. and indeed, looking at the _parent_, it says `0x32983129d5f396e624049b22b9af04657aa6fcd8e566c935bb1ff6ad167e5d2a` is the parent --- which is the one all other nodes report for `11337655`.

Might be that we screw something up, and somehow maps the wrong numbers to hashes. We should look into it, and basically not permit a block `N != M` to be "registered" for height `M`


Start by reproducing the Cloudflare node discrepancy described in the report, comparing the block height, number, hash, and parent against the other nodes. Trace where blocks are registered and verify that a block with number N cannot be registered for height M when N differs from M; done means the mismatch is rejected or handled consistently.

Written by the indexing model from the issue text.