I ran into this issue in mIRC v7.52.
Starting with a clean installation:
Open mIRC
Under mIRC Options, open the Connect->Servers menu
Click Add to add a new server.
Description: Unencrypted
Address: unencrypted
Ports: 6667
(leave Group blank)
Click Add on the Add Server dialog.
Click Add again on the Connect->Servers menu to add another server.
Description: Encrypted
Address: encrypted
Ports: +6697
(leave Group blank)
Click Add on the Add Server dialog.
Select "Encrypted" from the list of IRC servers, and click the "Select" button.
Enter a nickname.
Click Connect.
Expect messages "Connecting to encrypted (+6697)" and "Unable to resolve server" (unless for some reason you have a host named "encrypted" somewhere on the network...)
Click the Disconnect icon and go back to mIRC Options.
Under the Connect->Servers menu, select "Unencrypted" from the list of IRC servers, and click the "Select" button.
Click Connect.
Expect message "Connecting to unencrypted (+6697)". This seems wrong. The user has asked to use port 6667 when connecting to the unencrypted server.
mIRC will correctly pick the desired port for "unencrypted" (6667) if you edit the "Unencrypted" server listing (saving without making any changes is fine), then select it and connect to it. This gets messed up again if you connect to "Encrypted" again.
Another way to resolve this issue is to edit the "Unencrypted" server listing and put it in its own Group. It seems like you get the same weird behaviors if the "Encrypted" listing is in the same group as "Unencrypted".
