I have an external library which is shared using partner sharing. All photos are stacked (jpeg+raw) into pairs. It works perfectly fine for me(admin and owner) on web and android.
My partner sees everything perfectly fine in the iOS app. On web the stack image(top right) is shown on the thumbnail but once selected, the stack overlay at the bottom left doesn't appear.
GET /api/stacks/uuid returns 400
{"message": "Not found or no stack.read access"}
The same request loads correctly when I'm logged in the browser. The only difference I can see is different access token used.
Tested using v2.7.5 and latest main
.