Small Stone bypass pop

[LaceSensor]

Hi all

I build the Tonepad small stone

With the feedback / colour switch off, everything works great, including the bypass (standard true bypass madbean style)
With the switch on, the phaser works right, and sounds awesome, by the bypass pops loudly.
Ive tried a new switch to rule that out, and also adding pull downs.

Very frustrating.

Any advice?

thanks