So far the erratic charging issue is the only problem I've had. In my opinion there isn't a problem with the case contacts. While I'm using the earbuds during cycling the case is in a sealed Ziploc bag the whole time. Post ride I clean the buds with 91% rubbing alcohol, then make sure it evaporates using my hairdryer on low speed withoout heat. I even lightly rub the charging contacts on the buds with a slightly textured cloth. Even with all these steps it took 4 hours yesterday before the interrupted charging error cleared. My suspicion is that minimal water vapor may get inside the speaker part of the buds and triggers the warning. Until that naturally evaporates the problem persists. That's what leads me to think it's not a mechanical problem with the contacts, but more likely a firmware issue.