I'm wondering if you are overcomplicating this with the duplication of rules... which might also be triggering this behaviour in Trados Studio?  It looks as though are attempting to do this:

(Created by = TALGO\ykovalskaya OR Last modified by = TALGO\ykovalskaya OR Last modified by = TALGO\ykovalskaya) AND (Created by = TALGO\ykovalskaya)

Perhaps you can write in simple language what it is you're trying to achieve so we don't waste time guessing and give you something you don't want :-)

Hi, Paul!

the idea is to filter 3 types of segments:

1. created by a specific user

OR

2. last modified by a specific user

OR

3. created by AND last modifed by a specific user.

As for the third condition, maybe it would be covered by the first two and I am overcomplicating the issue, as you say. 

Ok, I will leave only the first two (hope they will not exclude segments that fulfill both conditions).

Thank you, Paul!

Unknown said:

As for the third condition, maybe it would be covered by the first two and I am overcomplicating the issue, as you say. 

Yes... I think it is.  If you were using filters, or wanted to set penalties perhaps, where the different subsets of the TM based on your criteria were important then that would make sense, but for the usecase here I don't think it's needed.  So I would try this and see if that works for you:

Created by = TALGO\ykovalskaya OR Last modified by = TALGO\ykovalskaya

Paul, you are right , I did the checking and in case one of these conditions is fulfilled, the segment is returned correctly, including those where both of these conditions are fulfilled (I mean , the "OR" condition is not excluding them, cause this is what I thought would happen).

Thank you, as always, for your collaboration!