Mike,

Charge at no more than 2.2A or 1C (Samething) - shouldn't be taking 3 hours tho.
Does your charger state what it's charging at? If so, what is it?

How much capacity is the charger putting back into the battery? Should show mah.
Are all the cells showing as balanced? eg: All the same voltage?

Sounds like a bad cell in the battery, or the charger underperforming (alot)