Gotta tell you Cronus, I've never actually had that happen unless I dried a cigar out accidentally in my car's ashtray. Like you say, a low of 64 should not dry them out, and it definitely would not over humidify them. The only thing that occurs to me that could have happened was that since it was in tupperware instead of a wood box, the evaporation of the water in the cigar may have triggered some chemical reaction with the lack of air exchange (excepting the opening of the tupperware as you said you did). I'm no chemist, but I would think that letting something dry out in the absence of oxygen flow might have some sort of detrimental effect. You might try putting them in with a selection of the good tasting ones for a week or two to regain strength, but I have no experience as to whether or not it will work.
I know its not going to help for this situation, but if in the future you get some over-wet cigars in the mail, I would recommend that you let them dry box for a few days (place in a cigar box or other almost airtight container until they reach a consistency you feel comfortable with).
Another thing I just thought may have happened: since you had the cigars in with the ones you did not like (I assume either young or tight draw, or some other common flavor or construction issue) the humidity of the wet sticks may have made a migration to the less wet "bad" sticks, sending a few of the essential oils with it.
Sorry all I can do is guess, hopefully one of the other pros on here will have a well founded opinion. In the mean time, have another of the ones you really enjoyed. It'll take a little of the edge off.
Cheers and happy smoking,
Zach