All I can suggest for you now is to delete any Ultimate Member plugin or addon and do a clean of your database and remove any residing value to Ultimate Member, as well as WordPress caches.
Then once you know everything is clean, simply install the Ultimate Member plugin again and it should be active for you.
The mismatch can be taken out of the code, however given the amount of times that this plugin has been downloaded, it has not been a common problem to have to had removed it.
I have tested the main download on local, sandbox and live sites and it works fine on all.
Just tested again on sandbox and simply installed Pro from here and activated it, got told to install and activate Free version, so did that and this is the result.
i deleted the plugins and reinstalled from scratch. despite this the problem persists. I don't want to clean up the database data for the many settings created, it would be an important job to redo from the beginning :-(