Sound issue - Abyssal depths lich music cuts

I am playing on PC standalone, medium channel count for sounds.
I play with summon skeleton mages, which create a ton of projectiles.

The Abyssal depths music that plays when there is a lich (it was Ulaman) cuts whenever too many skeleton mages attack. The music also doesn't start over when it comes back. Other kind of musics play normally regardless of the number of projectiles.

I feel like the Abyssal depths lich-specific background music doesn't have the normal music priority on sound channels.