I do have Phonak rechargeable hearing aids (Marvels) and have had this happen to me in my left hearing aid, which is my best ear!

My audiologist said to hold down the volume button for 15 seconds, release and wait 4 seconds then put the aids into the charger. Eventually it will start blinking and this indicates it has been reset. I just reset both. This has worked for me.

My audiologist says resetting is helpful for various battery issues, but this is the only issue I have ever experienced.

Hope this helps!