I'm on a PC, Windows 10.

So I played through the force arena to stage 8.  Then I wanted to farm it, so I hit multi-battle.  I kept trying but every time it would end after the 1st battle and not play out the rest of the battles.  I don't know if it matters if I haven't beaten stage 8 yet.

Related but not the same, is this happened to me on a campaign level that I have multi-battled all the time.  Well I ended up restarting the game because it was on all day even after my computer went into "sleep mode".  That seemed to have fixed it.  This happened after my problem with the Force Dungeon, so I didn't try rebooting to fix it.

Okay GL :)