I don't know when it started, but is it possible to bring back the old filter behavior wherein:
(1) If you put a value in the "Create Multi column filter" then click filter, it will use that filter. (2) When you type a condition in the bigger filter box, even if there is a content in the "Create Multi column filter", the condition in the bigger box will be used. (3) Whichever is the most recent (bigger filter box or multi column filter), that is the condition that will be used in the filter.
What's happening right now is that, even if you type a condition in the bigger filter box and the "Create Multi column filter" is not empty, the "Create Multi column filter" will be used.