That is unfortunate, you were about to kill it too. This seems to be a pretty rare bug but we'll take a look at it and try to fix it. Do you remember what ammo mods you had? I think your own shot exploding near the droid stunned you and stacked up, and that might have also been what caused the boss to freeze there. I would guess it was Sonic Ammo or Concussive Ammo.
Patch 2.61 was released a couple of days ago as well but it shouldn't affect this bug. We added the first pass on a Minimap though that you might be interested in.