As I said in my posts, if you really read them, I reversed the pedals and they both POP when I switch from POST-POST to PRE-POST presets.

As a matter of fact, you don’t even need to replicate my setup of 2 H9, you just need to one for pre/post function, as you described in your page. And the poping is there in both. I doubt it is a H9 failure, but at this point I am sure that what happens inside with this pre/post doesn’t work well. 

Or it may be an amplifier issue. I will test with another amp that I have, and get back to you on that.