The Convert Address to Google Maps Link plugin seems to be at fault. It is overwriting the address fields in the Connections admin. This plugin should limit it open code to its own admin pages … it will may also break the display of the Connections entry details too.
I did not want to deactivate it since I do not know how you are using it. My suggestion would be to deactivate that plugin to see if the issue persists.
Hope this helps, let me know.