Definitely a major concern here.
If one cell is truly at 4.9V, then you could have a dangerous pack in your hands. 4.2V is maximum voltage for any lipo cell. I would check with a voltmeter first before condemning your pack as toast, sometimes the balance connectors have poor connections and can read funny. If you actually have 4.9V on one cell you should be very careful and do not use the pack again.

After typing this I figured maybe you meant to type 3.9, and 4.11, in which case this is reasonable. Next cycle balance charge at 0.2A, it will take a while, but should balance the pack perfectly.