FS2020 does NOT close completely on exit ?

[chopperaddict]

I have suddenly found that when you hit the "Return to Desktop" the sim appears to closes but when you look in the STEAM INTERFACE, it is flagged as STILL RUNNING.
It doesn't matter how long I wait, it does NOT close, and I have to use the "STOP" button to close it, which presumably can screw up some data settings in the sim ?

Does anyone know how I can stop it doing this and close correctly ?