Knob difficult to turn at times

Hi all,

I'm sorry if this has been covered already but I'm not sure I am using the correct keywords in my searches.

I have a 2012 AWD Adv / Elite. Sometimes when I turn the knob (the bigger one you use to navigate through the nav screens, it turns very easily but sometimes, it is super hard to turn (a lot more resistance). There are times when you really have to squeeze it hard to prevent your finder from slipping because it is so hard to turn.

I tried to associate the various resistance to external factors such as outdoor temp for instance. But I don't think there is a relation.

Any one else has experienced this ? Is there a known reason / fix for this ?

Thanks