Also, with their own Addon Manager folder and SEPARATED!
This will definitely resolve the issues.
Please stop repeating this.
The Addon Manager is correct as it is, and even if they were in "separate" folders, the problem would happen just the same because, obviously, is NOT caused by having shared the code, but because we must have made some changes that we would have done ANYWAY, so there's something wrong somewhere, which for some reason is only affecting FSX/P3D, but the proper solution is finding what it is, we WILL NOT CHANGE THE INSTALLATION TO MAKE IT "SEPARATE".
It won't happen, so stop asking.