Recently purchased a 500HDX because my old 500HD started having issues with the volume pedal control. Now with my new 500HDX installed I am having different volume issues? Basically anytime I program the expression pedal to control a perimeter that perimeter freezes up in one position? It isn't mechanical because I see the same issue with my Mission expression pedal as I do on the POD? It can't be a damaged POD because as previously stated I had similar issues with the expression pedal on my old POD. I suspected a corrupted firmware download but I have reinstalled firmware several times. Even rebooted back to factory settings with no success.