MR(merge-request) approval rule looks not working well

Hi all.
I am a owner of a project, and I want to check every MRs for every branch.

So I made a approval rule (the rule name: ask maintainer) in setting

Then I made 5 MRs by another account (Max) for testing.
But some MR is approved itself !!!

Some MR is working well with the approval rule (ask maintainer), and I can see the approve button.

But some MR is weird.
It’s approved itself, and I cannot see the approve button, and there is no my photo icon even !!

I appreciate it if someone explain about this…
Thank you in advance.