The current user may not need to have those rights if the maintenance service is installed, which allows the updater to run with higher privileges. I don't know

The current user may not need to have those rights if the maintenance service is installed, which allows the updater to run with higher privileges. I don't know of any reason why the recent updates would be any different, though. There may be an unrelated issue that broke "silent" updates for drtillberg. (I work on the Firefox updater and am a Mozilla employee)