I got my replacement keyboard yesterday and, so far, so good.
I used it for about 30 minutes with music playing while I played a card game app that, when active, seemed to exhibit significant random mutes with the previous keyboard. No muting with new keyboard.
After recharging a low battery, I used it for about 1.5 hours with music playing, doing various other tasks (news & weather apps, desktop & Office activities, and other game apps that had significant random muting). Again, no muting with new keyboard.
However, I did have an issue at one point with the keyboard apparently not being recognized about half-way through the second session. I detached and reattached it and it worked again. Hopefully I haven't traded one problem for another.