Quick answer: Pygame mixer.music.set_volume during an active fade producing a volume jump? Fade and set conflict; current fade overridden - cancel fade first.
Music fading out; player adjusts volume; volume jumps to set value, fade restarts.
Cancel fade first
music.fadeout(0)
music.set_volume(v)Stops the fade; sets directly.
Or queue volume changes
Hold pending volume changes; apply after fade completes.
Audit fade interactions
Each fade overlap with other audio actions. Document.
“Fades and direct sets conflict. Pick one path at a time.”
If your audio jumps, the fade-then-set sequence is the suspect.