We have noticed since Feb that when you run any UserControlHost page (not in model), this freezes the UI and the user must refresh/log back in to fix it.
This can be replicated for example by clicking Expand on the PowerBI Part on the role center, once you close this page, you are unable to click on "Show Me", Tile or any other item on the role center.
I am unsure if this links with the lookup bug reported on Item Lookup.