Hi,
This is embarrassing for me because maybe I'm doing something wrong and maybe it's obvious, but I'm not able to see it right now.
I execute this JQL below:
project = STS and created >= "2019/10/01" and created <= "2019/10/31" and assignee was in (e00002, a01559) order by key asc
It returns this issues list:

I execute another JQL, equivalent to prior one but with issue keys instead of created dates:
project = STS AND key >= STS-34490 AND key <= STS-36596 AND assignee was in (e00002, a01559) ORDER BY key ASC
It returns exactly same issues list:

But issue showed below (STS-34497) is not in the list and I can't figure out why. It seems that all JQL criteria is matched: project is ok, created date or issue key is included in interval searched, and user 'e00002' was assigned to this issue:

So, what is going on here? Am I doing something wrong? Perhaps I simply misunderstood use of "was in" operator? Or there's something more, like a bug in "was in" operator?
Our current version is 7.9.2 running over Oracle. I have successfully reindexed the instance but there aren't no changes in query results.
Please! Any help or suggestions?