Wow sorry to hear that. It definitely seems outside the norm. I've never had a pair break on me in about 4 years, and I wear mine to the gym about 4-5 times a week. Not at all careful with them. But, I'm also using the stock cable.
The aftermarket adapters are 99% likely the cause imo. How do the pins look when you take off the adapter? Are the pins separating? Are they missing any piece of the metal tip on the end of the pin? Does the issue persist if you reinstall the stock cable?
If you get another pair I would highly recommend using the stock cable and cinching it for easy over-the-ear wear. Completely eliminates microphonics for me. They are the best running pair of earphones I've ever had.
Really doubt that, given I have build some adapter myself and there isn't much that can go wrong with those things.
If I were in the same shoe, I'll check for DC offset on the source first.