Timeline unresponsive after v14.5

I guess this is an old bug (to which I never experienced until now), but the timeline becomes unresponsive when working with Masks, shadows, messing around with effects, etc.  I could still save and adjust settings in the Effect Controls, but I can do nothing else but to force quit Premiere.

I have tried almost every fix I could find previously from other users with unresponsive timelines, etc. From resetting workspace, resetting preferences, and deleting media cache.  Nothing. Same unresponsiveness happens 100% and I can't get anything done. 

But there was one work around, which might be connected to 14.5, given the recent update with GPU acceleration. I had to disable CUDA and use software only. Sigh, I know I can finally work on projects with this... but it's kind of unaccetable, since I never had to make this kind of workaround.

Any help or feedback would be great.  Thank you!

My Specs:

AMD Ryzen 3900x

Nvidia GTX 1660ti

64gb Vengeance LPX DDR4 RAM @ 3200Mhz

500gb Adata Nvme SX82800PNP 

1tb Adata SSD SU800

Windows 10