That's crazy, I've never hear anyone say this before and I've been on several cigar forums for many years.
I went through the exact same thing about 3 years ago and it lasted for almost 2 full years. Suddenly one day, cigars were good again. During that time though, no matter what I smoked it always tasted like dirt and bitterness, just like you're describing. I also got more sensitive to spicy foods.
I went to a dentist, an ear/nose/throat specialist, and searched through a thousand websites looking for an answer. I varied up my diet, got special toothpaste, everything I could think of.
Sorry man, I know the feeling and it's awful.
I started a new medication around the time the cigars started tasting good again, not sure if it was just a coincidence. I'll shoot you a PM.