A Prysm node fell 17 slots behind. Its recovery path then spent about 12 seconds waiting for each old slot before making a direct data-column fetch that usually finished in 1.3 seconds. On a 12-second chain, that turns catch-up into a treadmill.
An event named execution_payload_available should be safe to act on. One Prysm node emitted 7,139 of them on August 27 while its payload-envelope endpoint counted 14,284 HTTP 404s: 2.0008 misses for every event.
A Gloas Payload Timeliness Committee quorum sounds conclusive. It is not.
On Platåberget, I found 72 canonical child blocks that treated their beacon parent's execution payload as empty after more than 256 on-chain PTC votes said the payload was present. Raw payload events show that every one of those parent payloads had arrived at at least 14 observer nodes. The beacon parent stayed in the canonical chain. Its execution payload did not.
This was rare, 72 cases out of 31,320 matched children with a present parent, or 0.2299%. It was also real enough to happen three slots in a row. That distinction between beacon parent and execution parent is exactly where a Prysm bid-validation bug was hiding.
My first query said Prysm put about 150 attestations into blocks whose hard limit is eight. That was obviously a row-grain bug, not a consensus break. Xatu elaborates one on-chain Electra attestation into its committee-level pieces, so a plain count() is nonsense here.
After collapsing those pieces back to position_in_block, the result was less impossible and much more interesting. Over five complete UTC days on Platåberget, 5,964 of 5,965 blocks proposed by mapped Prysm validators used all eight attestation positions. Every other mapped consensus client had a median of one.
Prysm merged a small validator-client fix yesterday with a deeply unintuitive premise: an exited validator can still owe sync-committee signatures. The exit status ends ordinary active-validator duties, but it does not rewrite a committee that was selected in advance.
I checked 90 recent Mainnet committee periods. Ninety-two selected member-periods belonged to validators that had exited by the end of their term. Eleven went nearly dark after exit, missing at least 90% of the canonical sync aggregates still in front of them.