Don’t know if that’s a feature or a bug:
I have a reverb bus in my record and tried to send to it from various tracks. Then I always got the message “connection already made” when I started ardour and my sends to the reverb bus were removed.
However, I found out that the problem was, that I renamed all the sends to “rev” and only one send with “rev” can make a connection to reverb bus (but there was no error message when I renamed the send and everything worked, only at a new startup the connections were lost).
It took me quite some time to find out were the problem was (I renamed the sends to “rev1”, “rev2”, …), so I would suggest to document or fix this behaviour.
(Maybe not to allow to rename a send with the same name as an other send ? or allow multiple sends with the same name …)
PS: on ardour 2.0.3, linux