Finished render image has unfinished areas

[d3frage]

Hello,

The rendering takes about 1hour and vray says it's done... however the unfinished parts are still inside


Thats the only warning:

[20:40:40.566] Warning : Checking CUDA driver version: 5001: Installed driver version (516.59) is newer than the latest verified one (512.59)!

Thats the last Line in the Log
[20:43:30.049] Warning : Num samples per thread reduced to 262273, rendering might be slower

I rendered the Picture 3 times with different Image Width/Height.. problems are only at 3840x2160.. Cuda and Quality High+

Using a Ryzen 9 5900X
RTX 3080 Ti
64 Gig Ram