It was not possible to add these server entries through the mIRC interface. Server entries are uniquely identified by their IP or Host, so creating a new entry with the same IP/Host will delete a previous entry. I had to add these entries by hand to my server.ini file.
I have not yet been able to reproduce this issue here. I have added multiple entries with the same descriptions, addresses and ports through the servers dialog without any issues so far. Are you sure that this is happening with the latest version of mIRC?
