The exact same bug as this one but it only happens on theorytabs
Notes splitting into two across key change: https://www.hooktheory.com/theorytab/version/id/734349
Notes and chords splitting into two across pickup measure: https://www.hooktheory.com/theorytab/version/id/722635
@Vaz, thank you. I pushed the 2.16.2 build of the hookpad player to production which resolves this.
EDIT: 2.16.3 fixes this for pickup measures also.
@chris chords still split into two across a pickup measure