[Bug] Graph-node save incorrect block cache during reorgs

Bug report

In case reorg happend and graph-node has seen it we would have 2 entries in the cache table:
Example for reorg on ethereum mainnet on block 17820205 with depth=1

graph=# select hash, number, parent_hash from chain1.blocks where number=17820205 (https://etherscan.io/block/17820205/f)

                                hash                                |  number  |                            parent_hash                             
--------------------------------------------------------------------+----------+--------------------------------------------------------------------
 \xdcb02b80a71bb335a8247298cfde2af9f589b491a1eb794a88fa377fb00e6fb8 | 17820205 | \x9432a65af5ecd186859c22bf4d809561aaa4daf3bf8101fccb3f228e34b64756
 \xc0455fae763cd8d53bc294cbd32225f207dee56cb396aee84eaaa5011513731a | 17820205 | \x9432a65af5ecd186859c22bf4d809561aaa4daf3bf8101fccb3f228e34b64756
(2 rows)

graph=# select hash, number, parent_hash from chain1.blocks where number=17820206;
                                hash                                |  number  |                            parent_hash                             
--------------------------------------------------------------------+----------+--------------------------------------------------------------------
 \x409c0bb686a5fac90e706a556d02cf99122b49c683374c82341cccc836807964 | 17820206 | \xc0455fae763cd8d53bc294cbd32225f207dee56cb396aee84eaaa5011513731a
(1 row)

graph=# select hash, number, parent_hash from chain1.blocks where number=17820204;
                                hash                                |  number  |                            parent_hash                             
--------------------------------------------------------------------+----------+--------------------------------------------------------------------
 \x9432a65af5ecd186859c22bf4d809561aaa4daf3bf8101fccb3f228e34b64756 | 17820204 | \x737d8549261f685b18b6c6f2dac460c6dfc4b88bf16b03d2a813ed51f9c08c40
(1 row)

From our experience that sometimes cause errors in subgraphs, because the subgraph takes incorrect data from the cache (This need confirming)
We had a problem when the subgraph was stuck until we remove duplicates from the cache.

Relevant log output

No response

IPFS hash

No response

Subgraph name or link to explorer

No response

Some information to help us out

• Tick this box if this bug is caused by a regression found in the latest release.
• Tick this box if this bug is specific to the hosted service.
• I have searched the issue tracker to make sure this issue is not a duplicate.

OS information

None

Start by reproducing the reported SQL queries against the chain1.blocks cache for the cited reorg at blocks 17820204–17820206. Trace how reorged blocks are saved and selected, then verify whether duplicate block entries can make a subgraph use incorrect data or become stuck. Done means the cache behavior is confirmed or disproved with a regression test or documented reproduction.