scubapro g250 g250v sticking locking

Hi, I have a G250V that has about 15 dives on it, and after the last dive, the Inhalation resistantance knob is sticking. I always soak the regulator is fresh water after use for about an hour or two. Basically, after it's all dry and put away, after about 3 days, the knob sticks at it's...