This is an issue that I'm experiencing on my Samsung Galaxy S24 Ultra. This does not happen with my Samsung S21 Ultra. Like the title says, after a couple of minutes of staying in the instance the mic starts cutting out, which I learned about it after one of my friends told me. Rejoining the instance may temporarily fix the issue but starts occurring again after a while. This happens despite having good internet speeds and connection, which I currently have download speeds of 100mbps and upload speeds of 10mbps and at an acceptable distance away from the router/modem combo at home with no reported outage from the ISP.

Not every compatible device might be able to reproduce this bug.

Edit: I added a video that shows the bug in action, made possible by using an alt account that I own for recording. I was deliberately making noises like rubbing the phone on the bed sheet and using a portable fan in front of the mic for this purpose. After further testing, I noticed that some worlds are not affected by this, so not all worlds are able to reproduce this bug. From the worlds I've tested, the ones able to do it were Abyssal Seas Remeshed (where the video was recorded) and Pocket Rain by Silyataru, Winter Company by Lucifer MStar, Ethereal Escape by Kireya, Cozy Boat by Lealennia and The Black Cat by spookyghostboo, just to mention a few.