My issue is still the private key import a new address in new Electrum (anything after 1.4 I tested) . When importing in old Electrum 0.34 bring up my original address.
The only possibility that I can think of which would cause this is if there were some sort of bug in 0.34 that is creating an "invalid" address from your private key whereas the new versions are creating the valid address which is the reason for the difference. (BTW I already pointed out
this is not a compressed/uncompressed issue).
I'm curious, can you spend from your address or sign a message from it in Electrum 0.34? Because that would clarify a lot of things.
I am not sure because my son is not at the same premises at the moment. All I know is that it is not watching only and it brings up the correct address moment it is imported. When I have more detail I will post it here.