I may have encountered a problem. When I used the shortcut keys in the viewer to quickly zoom in and out of the picture, such a black area appeared, and it can be reproduced stably.
This is the download address of the video file
The attached video doesn't seem to play here, and the download link has been deleted (after the first download, it says).
What are the keys that you're pressing, so we can try doing the same thing?
What type and size of image is it?