glitchy/pixelated footage in both preview and output

Hi all. For a while, I have had this problem with premiere (and even after-effects sometimes) when I'm playing footage in the timeline, this weird glitch-looking thing happens in some frames. When these glitches are previewed in the timeline, they are also carried into the export, but they are not present in the source footage. The only fixes I've found is that when I close and reopen the project later in the day, *sometimes* is goes away (very infrequent) or I replace the footage with the same footage but just straight from the source again, which can be a real pain if there are multiple clips with this bug. Any suggestions are appreciated.