This is an issue that I'm expriencing on my Samsung Galaxy S24 Ultra. This does not happen with my Samsung S21 Ultra. As 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 about it. Rejoining the instance may temporarily fix the issue but will occur again approximately for the same duration. 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.
Not every compatible device might be able to reproduce this bug.