After getting one of my Aperture Libraries into PM+, I see that I have about 30k pictures that have no keywords at all. It's not the end of the world at all, in fact most of the info I need to add these keywords is in the caption, so I have been chipping away by filtering/searching for pictures that have no keywords, then doing a search on the info in the caption, and then batch adding the proper keywords in the keywords panel. The problem is that after I add the keywords, I refresh the contact sheet, and there are more pictures that fit the initial criteria (no keywords, but with the relevant captions). It generally takes 6-8 cycles to clear the original search no matter how large it was in the first place. The number of files "found" each refresh is different also, so there's no pattern there.
I know I haven't mastered the best ways of isolating pictures in PM+ yet because it is SO different from how filter/search worked in Aperture, so I guess I'm asking if this is a bug or if I am missing something I'm supposed to do. I could make a screen recording if that would help.