Both the ability to play custom browsers and the ability to play bookmarked files are not working.
There’s a thread about this here, OP: https://www.halowaypoint.com/en-us/forums/e0d9938206f04a598ce84f2c8cadce02/topics/regarding-ugc-in-halo-5-maps-modes-films/8387dc20-e62c-4227-b849-3421468c68e7/posts