Ah, a patch must have gone through when I was actively trying to fix a menu-related bug I found. I should have wrapped the changes around dev-mode, but I didn't realize a hotfix was going to be pushed so soon. This lock should only affect some items that directly route back to the inventory (though it is hard to tell that from the player's side--it was primarily for items that had a sub menu after use, that would them pop back to the inventory rather than the main game screen). When I realized this bug happened during testing, I did fix it with a better solution that didn't result in empty buttons like that. So hopefully this should be resolved in the next patch.
The bug I was trying to fix was a UI-related bug that deals with push/pop of the UI states. The crashes are only apparent in dev-mode builds, so the release builds are playable just fine, even if they run into those issues.
The broken solution I had was that it would queue up returning back to the inventory after an item was used and there was a main game screen element in the UI history. This worked for items that used a sub-menu and dropped into the main game screen, but I only realized it was a bad edit when I saw that some items would force back into the inventory after their sub menus (like Dumbfuck). So essentially there were two inventory UI calls. It's the second inventory call that cleared the main game menu buttons.
The new solution basically digs into the UI history and sees if the main text UI element exists in the history before returning to the main game screen. If it does, it should clear the UI history. This would resolve the dev-side crash of stacking matching UI states for item sub-menus dropping the player outside of the inventory and not add any extra inventory UI calls.