Distorted sound when pitch shift control is activated

[jackspm]

As the title said, playing audio with pitch shift activated generated distorted sound...mainly on the low frequency. I'm not a musician so I'll try to describe it with my best effort.

The bass sounded broken, cracked...as if like the speaker is blown. It also sounded like a low frequency rippling.

Move the slider back to zero semitone will restore the sound back to normal.

Any idea on how to fix this? Or is it a bug? I'm on version 3.0.11.

Thanks.