Sync committee contributions did not restart after nodes resynced

[benjaminion]

A report on Discord from EvilJordan following the Besu incident. When the clients regained sync, Teku failed to produce sync committee messages.

As I understand it:

• The validator was assigned to the sync committee at the time the Besu incident occurred
• The user recovered the node and got back into sync
• Teku started correctly producing attestations
• Teku did not produce sync committee messages, although it knew it should do, reporting Sync committee performance: epoch 254663, expected 32, produced 0, correct 0, included 0 (0%)
• Restarting Teku resolved the issue and sync committee contributions began to be produced.

It seems like Teku should have automatically restarted producing sync committee contributions when it got up to the head of the chain, but did not do so.

[EvilJordan]

You got this exactly correct. Happy to provide logs if necessary, as long as someone helps me narrow down what to provide.