Mission Quit in already started campaign won't function

[Falken2]

I started the campaign "Cage the bear" on 2.5.6. stable. I was on mission 3 "Cargo". I installed 2.7. 

 

When I complete the mission, the Green button on debrief panel "Mission quit" is stuck, so you have to close the window and you can't progress in the campaign.

[Flappie]

This issue is discussed here: