One DNG is bogging down LR, especially the masking brush (M1 MacBook Air)
First of all, I've resolved the problem by resetting the edits and starting over. However, I would like to know what I might have done wrong, so I might avoid this in the future.
The DNG is 24 MB, from a Canon 6D Mark II. When it's open, LR generally lags when switching between modules, but it really boggs down when I open the masking panel. Toggling the overlay takes about 5 seconds. It takes 3-4 seconds to see the effect when clicking a mask's "eye" icon. There is several seconds delay between painting and seeing the stroke appear in the overlay, and as I move the brush the overlay appears in little blocks, instead of going down smoothly. It can take up to 10 seconds for the stroke to show in the history panel.
Here are the masks (2 gradients and 4 brushes):

I optimized the catalog, deleted and re-created the 1:1 preview, and turned off the graphics processor, but it didn't help.
Is it possible for a specific file's database entry to get randomly corrupted? Is there a way to rebuild the entry without starting over? Anything I might have done to corrupt the data?
Thanks,
Russell
