During Amoral Combat, the security door to the arena (on the player's side) would not open and the terminal option to open it was also disabled so I had to tcl through it to advance the quest (several times on repeat visits too)
Again, listed as a verified bug on the wiki:
"When the next opponent arrives in the arena, upon heading there the mag-lock door will not be open, which prevents one from entering the arena to fight the combatant"
http://fallout.wikia.com/wiki/Amoral_Combat