Did some further investigation. I have about 8-10 airports installed in the documents folder, but I only have this problem with 3 of them. The 3 airports causing this problem are based in Scotland/UK, for which I also have ORBX England and Scotland. However for the other airports (in Poland, Russia and Estonia), there are no alternative AFCAD. It seams GSX for some reason favors the ORBX England/Scotland AFCADs even though England/Scotland have lower priorities than these 3 airports (EGPK, EGLL and EGCC).
Just to confirm the issue I tried disabling EGPK in the documents folder and then manually install in directly in the P3Dv4 folder, and this "fixed the issue", however as LM is suggesting developers to use the dokuments folder, this shouldn't be an issue !?
Pelle