Transpose feature is adding a harmony - help please!

Are you certain you aren't hearing the effected note AND the acoustic sound of your guitar together?

99.9% of the time....that's it.

Ruefus, your statistics aren’t quite accurate. I believe the figure was 99.9999% of the time 👍

how are you monitoring the signal?

Have you tried to record the signal to see if the resulting recording is also suffering from the "harmony" issue?

I hear a subtle tremolo effect on the sustain tails when using the Transpose with iso headphones. Could that be the same thing OP is hearing?