I was trying to update the archipelago mod in steam workshop and after hanging for a few seconds, got an error popup:
While preparing this bug report, I started filling the mod update inputs (name, desc, change_log) for a second try, but before finishing adding the texts, the workshop overlay suddenly appeared, showing the mod page and the mod updated correctly (? I guess) from the previous try.
Checking the steam workshop through normal steam app (not the in-game overlay) shows that the mod is indeed updated, though the size is reduced to 17mb, which I guess (and hope) it is just the new compression method you guys mentioned being used recently