Thank you for reporting this.
But I'm sorry, I couldn't reproduce that bug in my environment.
Does the music start playing from the middle?
Or is it taking too long to load?
These are the reasons I can think of now.

https://haya-prog.itch.io/colane-test
CoLane is the typical rhythm game, but the lane will switch.
When the multiple keys are the same lane, the note coming there can be hit for any key of them.

There are 2 tutorials with 1 music, and 12 charts with 6 music now.
Please play and give us your feedback! It will help us make the game even better!
Trailer: