E.g. there could be a cache that (incorrectly) returns a reference to a cache item without any locks being held by the client and reuses cache items on eviction

E.g. there could be a cache that (incorrectly) returns a reference to a cache item without any locks being held by the client and reuses cache items on eviction. Then if an eviction happens before the client is done with an item, there is a data race between the client reading the item and the item being updated into the new, unrelated, cache entry. Although, if that were the case, I'd expect various partial mismatches to also happen.