Title says it all, really. When you add a new collecion that contains an underscore in the string, the game manager will not load that player's inventory anymore. The page will just be blank. When calling GetInventoryCollectionIdsAsync via the API, it now returns none of the collection id's (even none of the ones I previously had that don't contain an underscore.)
Secondary question: I can't seem to add an item to a player's inventory at all. No matter what I try, the API returns "Asset (FriendlyId/itemname) was not found." I've tried using the FriendlyId and using the internal id directly copypasted from the catalog, but both yield the same result. I'm logged in as title entity, so it can't be a policy issue either. Maybe it's related to the above issue, I don't know.
My title id is 770E4 in case you want to check things out.