After updating via osu!client the map's background becomes default again because the .osu file has been changed to it's original state.
Because osu! client checks for all .osu file changes (Even in //Background and Video events see: ) the changing to custom backgrounds would result a map being unranked.
(the only thing i can think of is changing the osu default background to something else, however I don't know where it is being stored)
After updating via osu!client the map's background becomes default again because the .osu file has been changed to it's original state.
Because osu! client checks for all .osu file changes (Even in //Background and Video events see: ) the changing to custom backgrounds would result a map being unranked.
(the only thing i can think of is changing the osu default background to something else, however I don't know where it is being stored)