Consistent Lag, teleportation, and Midi Artifacts

[Order]

Player consistently lags behind a note for a while each time you start song

When did this start? When the new smooth scroll was introduced, or before that?

EDIT: I mean, I know what caused the other 2 bugs, and how to fix them, but I'm not sure about this one.

I've only noticed this one since I posted my original thread here asking about it around two weeks ago (June 4). I was making songs daily before that and it didn't happen.