Considering Steam’s API is vomiting over itself at the moment, it’s surprising that Tower Express consistently works for purchasing items. Is there a method PT could use to enable to purchasing of new condo types over Tower Express? I’m not a developer, so I can’t claim to know how condo purchases/unlocks are handled, but they do seem to rely on a similar transaction system to items.
From what we know, the issue isn’t from granting items, but being able to determine if the user has the item. Steam seems to be unreliable with telling us and the game client what items you have in your inventory.