So I’ve had these for about a month now and haven’t seen any condensation even after wearing for over an hour at a time. And I’m the sort who tends to sweat fairly easily.
Now before anyone gets upset, I’m not denying that this is a legitimate issue, only pointing out that it seems to be based on the conditions in which you use them.
Given their size, weight, and the fact that they're not at all water-resistant, it’s evident they were not really designed for use during any sort of exercise, nor in very warm/humid conditions. I can imagine how disappointing this must be for those who expected otherwise, and it’s fair to suggest that Apple should look into tweaking the design to provide better ventilation and/or some moisture resistance. Perhaps the fix would be to offer an “active” version of the earcups. But barring that, the alternative is just to return them and seek out another headset more suitable for your individual needs and preferences.