Does Sotalol Cause Episodes Of Atrial Fibrillation?

I have been on Sotalol for approx 10 years and was recently changed to the Eon generic, after which I had two breakthrough episodes of Atrial Fib within 10 days. Prior to this change, I rarely had these episodes. Does the Eon generic for Sotalol contain the true 120 mg of the active ingredient that I need?