Lifetime handling of temporary kit seems wrong

Steps to reproduce:

• have 2 kits with different Qt versions / compiler configured
  (I had MSVC2017 Qt5.11 and MinGW Qt5.10)
• create a simple project with the MSVC kit from template
• build it
• close the project including all its editors
• remove the .user* files of the project directory
• inside QC's options remove the kit and the Qt version that had been used to configure the project
• re-open the project and import the existing build
  • QC shows the kit / Qt as temporary
• hit 'Configure'
• re-open the options and fix the kit (compiler and debugger should be wrong)
• re-open the Projects view and disable all kits until the kits selection / configure panel re-appears
• this lists now 3 kits (the MinGW kit, the temporary MSVC kit and the fixed MSVC kit) - althout when checking the kits page inside the options I have still just 2 kits

Note: I would have expected to mark the temporary kit as being no more temporary as soon I modify the temporary kit.

Selecting the modified and the temporary kit (I could distinguish them by the content of the tooltip) you get a single configured kit, but with duplicated build configurations (Debug, Release and Profile and all of them again with suffix '2')