Do you have the START SILENT on/off for the THRU?

And is this happening using only one pattern or coming from another pattern?

Im asking these because when you have a Thru and the pattern switches to a new pattern with the Start Silent activated for the same track where a Thru is placed, there is a bug that creates a high pitched noise (sometimes really high and dangerous!)

Anyway, I dont know if this could be your case, i should try your settings…as soon as i do…i’ll share my experience here.