Unclear The finding does not say whether this changes which requests reuse the cache or only how quickly a mismatch is found.
What
Claude Code can reuse the start of a conversation already sent to the model, which is called the prompt cache. To do this, it tracks a fingerprint of each message sent. It now checks the next message against its recorded fingerprint first. If they differ, it stops and reports no match before comparing the earlier messages.
Why
A mismatch on the next message is now found straight away, without first going through all the earlier ones.
Something disagreesSomething we can check disagrees with this entry, or the writer said they could not settle it.
The writer flagged doubt
The finding does not say whether this changes which requests reuse the cache or only how quickly a mismatch is found.