Airpods are connecting to iPhone but only one works while connected to my Macbook. What gives?

I got my AirPods as a gift in November and I've not had any issues with them.

But now I can connect them to both my iPhone X and my Macbook and the noise for the connection works on both devices.

I can hear music and podcasts no problem on my iPhone X.

But switch over to the Macbook, only the right AirPod works.

I've reset the AirPods, disconnected them, etc. I've tried it. I don't understand how it can work for my iPhone and only one work for my Macbook.