Created a room with two admins, (one user on matrix.org, the other on another HS)
Added an Etherpad widget to the room using the non-matrix.org account
Riot 2:
Logged in with the matrix.org account in an incognito window
Switched to the same room to find the Etherpad widget visible but seemingly pointing to a different Etherpad (confirmed by seeing the default text from the non-matrix.org account without edits made from the other Riot)
Riot 1:
Switched away and back to the room
Notice that the Etherpads are now the same Etherpads
Riot 1:
Riot 2:
Riot 1: