Airpods Max - Left Ear Cup

Hi guys

I've recently experienced a strange behaviour of my Airpods Max... it's about the left ear cup.

Unfortunately if the Airpods are connected to my MacBook (Pro, 13", M1) they won't play any sound at the left ear cup...

I only hear videos, music and every sound of the MacBook on the right side. Which is strange because all the Control Feedback Sounds (changing Noise Cancellation mode, Play/Pause,...) I can hear clearly on the left side.

Also if I use my Airpods with my iPhone they work properly on both ear cups. So I can't imagine that the left side is broken or something...

It's only "broken" when connected to the MacBook.

I've reset them already twice (also iCloud reset), charged them fully, rebooted my Mac several times...

Nothing works.

Can anybody help?

Thanks in advance.

Regards J