P: Sort filtered photos change the results number

If I filter my photos for eg with "December 2017", I get 609 photos. If I go to the bottom left sort option and for instance  select "capture date" suddenly my results are only  553 photos, If I select "reverse order" I now have 762 photos.
Then I deselect "reverse order" and  BOOM, look at this, now I have 559 results (not even consistent with the previous result that was 553)... And if I keep playing with the "reverse order" option, the results continue to be inconsistent for the same settings.

Also the "results filtered" that should be the amount of photos I have (30k+) also changes with the same inconsistency.

Lightroom, what the hell?!