It hangs up going between screens and even stutters scrolling sometimes. Its forgotten how to do widgets and I cant add them anymore. If I turn night light or grayscale on the colour shifts but doesn't go back if I turn it off, requiring a reset. A few other things... Should I reinstall it? Is there a chkdsk or malwarebytes type program I can use? Is it possible to reinstall the original pixel OS?
This would be my guess too. Weird things happen if files are left behind by the old OS. Otherwise they should be able to reinstall it, or the stock ROM using the instructions on the website.