Unfortunately, I also encountered this problem and I noticed it because during the Rome marathon, at a certain point the left headphone stopped working, I assume because it was discharged and the right only emitted a faint sound.
So I decided to return them on Amazon and I bought the Pro Buds 2, hoping that there is not the same problem.
I am very happy with this product, only that in the last few months they have started to give problems.
Many times with the iPhone the right headphone would not connect or other times the left headphone would not connect.
I never understood why there was this problem, I did nothing but put it in the case and then take them out and in the end they connected.
