Seems to be fixed as of June 21.
I think these links are meant to be set by selecting “add a connected column on connected boards as well” when choosing boards to connect. Even if you’re adding a board to a column which already is connected to other boards. My question below was just confused by the flakiness I’ve since captured on video.
OBSOLETE INITIAL QUESTION
I can’t find a way to control bidirectional connections after a connect board column has been created.
I have a single connect board column on one Board A connected bidirectionally to connect board columns in multiple other boards (B, C). If I link Board B from Board A, I see the connection reflected in both boards.
Now I want to connect Board D bidirectionally to the connect board column Board A, same as B and C.
If in Board A I select another board to connect to, Board D, and check the box to create a new connect board column there, the columns are not connected bidirectionally.