hey, i'm having an issue where Blender won't save images but just with this particular project.
starting with a empty blend file and reimporting all assets or clearing blenders preferences/profile wont fix it, maybe you can have a look

i've attached the file:
test.blend.zip

it just happens after "bake all", if i paint on the layers it seems to save the images.
so to reproduce the issue just do "bake all", see the * on custom bake layers, save file (CTRL + S), * is still there.
Close Blender, Blender will warn about unsaved images, click Save, Images are NOT saved.

the only image that looks like to get saved is "Ucupaint mage_shirt Color", all other images won't save

creating a new project, painting with ucupaint works fine, weirdly its just with this particular project