Inconsistent Selection Behavior

I'm getting inconsistent behavior when making selections of edits to perform operations on.
video to demonstrate--
https://vimeo.com/287321829/a25dec19cd
Having some kind of a GPU issue with my screen recording software. Apologize about the glitchy text.
video to demonstrate--
https://vimeo.com/287321829/a25dec19cd
Having some kind of a GPU issue with my screen recording software. Apologize about the glitchy text.