Questions

When trying to import a .ugs file for the whole collection on Android (browser or app), the app displays "loaded successfully" but does not update the collection.

From what I have tested this happens when you try to load .ugs file with the same name as a file you loaded previously. After clearing the app cache and browser cache and therefore resetting the app, it loads the old collection instead of the one you're trying to import. I assume that the file is cached somewhere with the name as identifier and upon loading a new file checks only the name and then loads the cached file instead.

Renaming the file resolves the problem and it loads just fine.

I just wanted to bring this to your attention.