I know the 1.12.2 version of Quark Oddities probably isn't being maintained, but this is such a small bug, it would be awesome if you were able to create a hotfix.

When a player wears a backpack from Quark Oddities in survival, the Aether Legacy's inventory icon is completely hidden, and the Aether inventory slots cannot be accessed. It's supposed to be visible on the bottom left corner of the player model box.

I really love Quark Oddities, but this one issue makes the Aether mod mostly unusable for my pack. :(

This seems like something that needs to be fixed on their end.