Hello, yes, I purchased one of these units at the start of mid April from Thomann and I'm experiencing exactly the same problem.
An annoying and audible noise floor introduced when the DRY/WET knob is turned to WET.
I've tried everything to reduce it, lowering the gain and also clearing the feedback when changing presets - but it still happens.
A little frustrating. I have contacted Intellijel and will update when I have more information.