I apologize for that bug, I use Fl Studio and never have I heard this. If you need a screen capture use OBS maybe? That's what I use to Stream and capture things just use a monitor capture and it might get it for you. I can feel your pain.
Aside from that, wow this is pretty good! I hope you can get your bug solved, if you are able to record it - message me and I'll try my best to figure it out for you