WiredTiger can return the wrong value when performing multiple timestamp based searches using the same WT_SESSION handle.
This was originally started in
WT-5119, but I believe the set of recent mismatch failures are a different problem than the original one in WT-5119. That ticket deals with an empty value that appears while repeating within the same transaction, and this ticket deals with modify records (so far).
The original failure was on margay-aws: http://build.wiredtiger.com:8080/job/wiredtiger-test-format-stress/71695/
And a third on kodkod-aws:
I will copy some of the analysis content from
WT-5119 to this ticket for completeness.