Fusion Mask Paint manual refresh

When in Fusion I have about a 350 frame clip with about 120 frames with strokes to mask out part of the image.

It seems that the composite image will occasionally show as if no mask was implemented. Interestingly, I've found that if I Invert a stroke and then Invert again, back to the original composite, the image will display the composite correctly. However, if I advance a few frames, the composite will again show as if no mask was implemented. I can do the Invert thing and it will again fix the image. But by the time I get to the end, I've noticed that the problem arises again at the beginning.

It seems like a caching or memory issue, but I've turned off all caching (that I'm aware of) in the main Project Settings. I am wondering though when in Fusion, the timeline has a green indicator for when a Fusion frame as been processed. Is this another caching that I can shut off? Maybe this is running out of memory? I have 128gb, was hoping that would be enuff.

I've also tried placing an empty Text object on a track above this clip (apparently a hack that sometimes works), but not for me.

Please advise. Thanks

Okay, I'll include some images to help describe the problem I am encountering.

The setup is I have an actress in front of an overexposed window. The correction plate is of the same shot minus the actress and exposing for the exterior of the window. The traveling matte is necessary at times to allow the hand with the phone to pass in front of the properly exposed window.

This first image is showing the Left viewport as the original overexposed window and the Right viewport shows the properly exposed window.

Correct

BMcorrect.jpg (184.01 KiB) Viewed 582 times

However, this second image shows what I encounter a few frames later. The Right viewport looks exactly like the Left viewport as if nothing was done to it.

Incorrect

BMbad.jpg (175.89 KiB) Viewed 582 times

I usually, but not always, can fix this discrepancy by unchecking and then re-checking the Invert box in the MaskPaint tool panel on the far right.

FYI, I just realized I had an unnecessary Merge in there, but still the same problem even after bypassing the Merge1 node.

Also, as of late, when I try to do a Quick Export or a render of this section of the main timeline, it will render a little bit and then cease rendering. It won't crash, the remaining time will just continue to increase in time. When I press to Cancel or abort, nothing happens. I have to Cntrl/Alt/Del to terminate Resolve.

Please advise.

I don't use that tool enough to help. Sorry.

Maybe ask in the Fusion forum, where those experts hang out?