The ost we heard from cbt was not loop but play in a playlist selected for that map.
My suggest is fix/lock a ost to 1-2 maps, make it a signature of the map like when we play “that” game (You know what game) 
I don’t know, I prefer having 1-2 tracks per map instead of one. Also, it seems the tracks are selected based on map type, like Gele Plateau and Tenet Garden having the same selection because of the same grassy-flowery map type.
While it make music more memorable in my opinion, some track might get you SUPER ANNOYED after couple of hours.
Oooh that Xmas dungeon music… Eugh.