Is Anyone Else Having This Issue?

Known bug, fixed in 20.0.1.

Check "Legacy Compositing" in Preferences > Performance to confirm that this is indeed the same issue. That should make it go away by reverting to old compositing code.

Can you explain what the issue you have is? It looks like you have done quite a few brush strokes on a layer mask and did a save.  What is the issue I should see here? I see a small white area in the Layer mask Thumbnail but the Image is zoomed to 200% and the windows has scroll bars I can not tell if the area the mask is allowing to be seen is on screen or not.   Is it the odd green color on parts of the house dormer window frames? What Mac OS version and what Photoshop version are you using?

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