Ever since the Winter update i’ve been unable to “quit” halo from the xbox home page. Once I hit “quit” it will prevent me from returning to the game, but doesn’t seem to stop the actual program, which then prevents me from playing any other game or app until I do a full system restart. Very frustring.
I was having the same issue. Turns out I was enrolled in the Beta Preview in the Xbox Insider app. I left the program, the xbox rolled back it’s OS and the problem seems to be fixed. Hope this helps.