As seen in #62359, kvfollowerreadsccl.canSendToFollower started using a significant amount of resources in the week before Feb 19. The following flame graph shows that this was via DistSender.sendToReplicas, with the majority of the time spent in pgerror.Newf via checkEnterpriseEnabled.

The offending PR was #59571, kv95 benchmarks show a drop from 60712 ops/s to 55565 ops/s (median over 5 runs) for this commit.