Quick answer: GameMaker sequence position visibly stuttering when game pauses one frame? Sequence advances on game tick; pause skips the tick - sequence visibly catches up.
Cutscene pauses for one frame; resumes; sequence position jumps slightly.
Use unscaled time
Sequence time source = real time. Pause doesn't affect.
Or smooth via interpolation
Tween position to expected; jump invisible.
Audit cutscene pauses
Each pause's effect on running sequences. Document.
“Sequence time matches game time by default. Mismatch surfaces on pauses.”
If your cutscenes show stutter, the time source is the suspect. Test pause cases.