Inconsistent results in activity streams

Hello, we are using Atlassians functionality to retrieve Jira activity streams.
We have noticed an inconsistent behaviour when retrieving results on different timeframes.

For example if we are retrieving activites for user1 for today (14th of march 2023) we would use request:
Results for that day would for some cases be different than if we retrieved result for a whole week and filtered out only today’s activities (date range from Monday 13th - Sunday 19th) :

Are we doing something wrong that is causing this inconsistency or is this a known problem?
Also many times we notice that using operator AFTER in conjunction with operator BEFORE, for specifying interval, returns different results as opposed to using BETWEEN operator for filter “update-date”.

Thanks in advance!