Well, I don't think my humidity is entirely to blame. I just smoked a Don Kiki Green last night. Nothing fancy, but a nice smoke while grilling or something. It tasted just fine. It's been in the same humidor for the same amount of time as the others. No doubt the sour one was a little moist, but also no doubt it was just a bad cigar too.

The salty one's burn problem was something someone called "booked" tobacco? I guess the leaves were simply stacked flat and rolled haphazardly? Apparently, that causes a hot burn chimney up the middle from a hole in the middle of the roll, and makes it very difficult to keep the edges lit because the leaves are packed together real tightly. The terrible burning this causes produces all kinds of strange off-flavors. Quality control at even the lowliest of factories should have caught this, but apparently, some sneak through. Badly fermented tobacco is also a possible culprit.