All still images imported into timeline appear distorted/glitchy.
I recently updated to the latest Premiere Pro CC version 12.1.1. Initially I thought it was just PNG files that- when imported into the timeline- ended up like this. But since testing it [with different file types AND on different versions of Premiere Pro CC], ALL still image file types end up glitched out with all these artifacts. WHY? This is hugely affecting a client timeline.

I am running El Cap 10.11.6, 2.3GHz I5, early 2011 macbook pro, Intel HD Graphics 3000 512 MB.