Problem
Sup! I've been trying to make a layout but the Start Pos triggers are desyncing the gameplay from the music. I also noticed the further the Start Pos are to the beginning of the level, the more it desyncs the music.
Testing
To test this, I put a timer at the start of the level and made it stop at a certain place. The first video shows gameplay from the beginning, and you can see the timer stops at 75.41 seconds, meanwhile the second video starts at the furthest Start Pos, where you can see the timer stops at 75.05. Testing from Start Pos that are in between the two extremes, shows that the timer stops at a lower number the further to the start, as I pointed out earlier. Also, this times are not consistent; with multiple runs, the first timer stops at 75.43±0.02 while the last stops at 75.05±0.02 (from what I've tested so far).
This happens while testing on the editor and testing in-game. Finally, the play green line syncs as it the music started at the beginning of the level, so playtesting becomes harder the longer the level is.