As mentioned , early on ( I only received the H9 MAX on 3/21/15)–the encoder was easily pushed using a light touch from my foot (w/o shoes) or simply lightly pressed with my finger. Just yesterday it seemed less responsive and the "click" went away and now I need the strength of both thumbs or heel of my foot to activate.
Used to be if I pushed anywhere (lightly) on the encoder it would work–now it must be pushed on Dead center–just saying.
I did forward initial issue to support as you suggested–just waiting to hear back.
Of course I could simply return to retail store (GC) as I have had it less than 30 days.