Good Lord! Who's your mechanic? Larry, Curly, or Moe?
An old Groucho Marx dialog:
Patient: "Doctor, it hurts when I do this" (patient bends elbow)
Doctor: "Then, don't do that"!
Seriously, it sounds like the compressor sensor hasn't been connected. It's job is to adjust the idle whenever the compressor kicks on. It may be since the electronics hasn't determined that a compressor is present, when the clutch engages, it senses a load and determines that it is due to a change in driving conditions and downshifts to give you more power.
Just a theory. Wait for another expert to reply to your post...
2009 ML350 (84K) - Family vehicle
2001 CLK430 Cabriolet (71K) - Wife's car
2005 BMW 645CI (124K) - My daily driver
2012 Mustang V6 (60K) - Daughter's car