I have deactivated the battle theme for normal battles, but it plays during Rodian creature master fights, so I would assume those are “boss battles”. However, Judgment, Sacrifice to the Light etc. still work, even though they shouldn’t work against bosses. I wouldn’t mind if this is how it remains just wanted to report the inconsistency.
Update: same “issue” with the “mini-bosses” in Eternity’s End , The Barrens, Bastion of the Void…probably the other versions as well.