Hello, I had the same problem and basically, as soon as the left one is on, you need to turn on the right earbud independently with your finger (long press).
Mat59
That is to say, pressing the earphone for a long time doesn't work anyway.
Revo Technology's products are a real scam. My earbuds came apart on the second day. They were supposed to send me a replacement, but nothing since January! The consumer association UFC Que Choisir told me there was nothing we could do since the company wasn't based in France and the website no longer existed. I also reported it to the relevant authorities to prevent this from happening again.