Pitch bender wheel of a MIDI keyboard

I've sent my Axiom Pro 61 for servicing this morning. It won't be ready any time soon. The problem is with the pitch bender wheel. When the knob is at neutral position and left untouched, regular MIDI activity was detected.

In Fruity Loops -> Debug, MIDI input kept coming in flickering the MIDI input activity LED. The same happens in Live. The normal behaviour should be no MIDI activity unless I've touched it by moving the wheel up or down. At neutral position, it should be zeroed and stopped sending MIDI.

How often does the pitch bender wheel becomes a problem like the above mentioned? I understand that different users have different mileage--the more you use it, the faster the wear and tear. It is common for users like us to send our MIDI controllers to have it serviced or part to be replaced? (potentiometer?)
I guess you've successfully isolated that the midi signal is coming from the pitch bend, right? It can come from various sources. No, pitch benders don't usually give the problem you described.