Kerbal Space Program

Theory: Something was done to the steam side of things by Squad/Intercept Games in preparation of 1.12.4 in the last week or so.

Problem:

Some people have steam trying to start KSP.app when on PC instead of KSP_x64.exe

Details:

One person said their version was 1.11.1 and the other was 1.12.3

Work Arounds:

1. 1 person fixed it by uninstalling steam and reinstalling however this is in my mind an extreme way to fix it.
2. I gave them instructions on how to use a shortcut to directly access the executable bypassing steam entirely and it worked.

Screenshots:
These are from 2 people on KSP reddit discord who had the problem. There were three people in total that complained of this issue out of the blue within the same few days)