Confirmed -- I can still make this happen on XUL client in 2.12.3, using the steps as described above.
However, the web client removes the "Merge Patrons" action from the Groups tab, so I'm tagging this as fixed in webby.
Confirmed -- I can still make this happen on XUL client in 2.12.3, using the steps as described above.
However, the web client removes the "Merge Patrons" action from the Groups tab, so I'm tagging this as fixed in webby.