The issue seemed to be Premier Pro CC Update related. I uninstalled Premier and then again installed the latest version and the glitches were gone. I have gone through so many blogs and forums having the same issue. Many of them did say that we need to update Premier and the CUDA software. But my issue was that the Premier installation 12.0.0 was not updating at all. It said "no new version available".
The best option I see is to uninstall Premier and remove preferences while doing that. Then the latest update shows up in creative cloud!!