My timeline preview renders stops before completing the render

Hi,

For some time my PP (latest version on fully updated Win 10 with Nvidia Studio latest version driver) has not been able to complete render previews - it starts, does some rendering and just stops and when done again does a little more (or sometimes nothing more).

This is very annoying. I tried to render the entire work area or just in-out - same thing.

My settings for previews are the common ones (below) - any suggestions? (I have seen some other users with this issue but no solution...).