Cannot find a library instance of "AceGUI-3.0" when AIO_Client is packed in an MPQ, no errors when directly placed in AddOns

[Routhinator]

OK, this is a weird one. I wanted to see if I could ship the AIO_Client files as an MPQ to avoid less technical family members from being unable to put things in the right folder.. and while everything seems to work fine - there is an error that pops up once on every UI reload when the AIO_Client is in an MPQ, vs when it's directly included - and I cannot fathom why.. potentially some race condition maybe?

Message: ...nfig-3.0\AceConfigDialog-3.0\AceConfigDialog-3.0.lua:20: Cannot find a library instance of "AceGUI-3.0".
Time: 03/04/26 06:55:35
Count: 1
Stack: [C]: in function `error'
...face\AddOns\AIO_Client\Dep_LibWindow-1.1\LibStub.lua:38: in function `LibStub'
...nfig-3.0\AceConfigDialog-3.0\AceConfigDialog-3.0.lua:20: in main chunk

Locals: (*temporary) = "Cannot find a library instance of "AceGUI-3.0"."

Ideas?