Erratic volume control on stock Mach460 Head

[cobra4v04]

My stock Mach460 has a odd issue with the volume control, frequently when I try to lower the volume it goes up. Sometimes it goes to nearly full volume and stays for a second or two before coming down even as I am turning the knob to lower the volume.
Anybody else have this problem?

 

[AntiHeightPunk]

happens in my girlfriends explorer too

 

[MLMike25]

Happens to me also. If I turn the volume down slowly, it doesn't happen. If I turn it down quickly, it does. I either turn it down slowly or mute it.