Update 5.09 broke the ability to enable or disable maps in the Map Manager. When selecting a map in Map Manager, the display becomes corrupted for a short time, after which a menu filling half the screen is displayed with details on the map file. This applies to both Garmin maps (e.g. TrekMap Italia v6 PRO Abbruzo, which I purchased for free to test) and 3rd party OSM-based maps.
I reported this to Garmin support, but thought it good to share here as well.