When your Grouping the Beam 2 with the two 100s are they all in the same room or is each 100 in a different room?
If you have been reconfigureing your setup things can get confused, a refresh can get things back to normal.
Power down all Sonos, reboot router and controller,power up the Sonos.
Each 100 is in a different room, but i tested them also in the same room as Beam and no improvement.
It works to group the 3 players via sonos app, but one Era 100 has no sound when all 3 are grouped… that player is not muted or something and it’s not the same player each time. It could be one Era or another without sound, depending on the grouping order.
Are both 100s on the latest firmware? They should both be on 16.5 (build 82.2-59204). To check go to Settings-Manage-About Your System. Scroll down to see info.