Threshold Alpha totally doesn't work in 2.10 but works fine in 2.08

[jupiter]

(10-01-2025, 09:09 PM)Ofnuts Wrote: Using a  layer mask (initialized with Transfer layer's alpha channel) and thresholding the mask also works.

Tried that, didn't work.

(10-01-2025, 09:09 PM)Ofnuts Wrote: Is the image color-indexed? In such images layer opacity follows non-obvious rules.

It's not color-indexed. There has to be some other property of the image or setting in GIMP that blocks or breaks Threshold Alpha settings. If not it has to be a bug.