Haven't had ANY issues with both pairs of mine!
I have to say that, while I was initially skeptical, I had received an amazon gift card that allowed me to buy a set of the earbud powerbeats about 2yrs ago. since then I have worked out in them and run in them, including in a 5k race. In all event situations, I sweat like a pig and the earbuds were completely soaking, with no ill effects at all. Other than wiping them off and charging them, they have been the best ear buds I have ever had; for sound, build quality, and comfort on my ears. I liked them so much, in fact (and I am an audiophile of a sorts) that I bought the studio powerbeats with noise canceling, for listening to movies and music on planes and in the home. Another solid purchase.
So I am not sure if my experiences are singular and I lucked into the only good (2) powerbeats headsets out there, or we are talking about some type of unreal expectation, like swimming with them or abuse. From my end, they have gotten WELL used and sweat- covered and still performed to a very high standard.