I can also confirm I am receiving a CTD with Stackhash error ONLY when installing addon manager with GSX, uninstalling GSX and Addon Manager results in no crashes
As I've said, there's something strange about this, because I can see errors (which you can't see, if you don't run P3D under a debugger) even WITHOUT the Addon Manager loaded, and they happens only with the Hotfix.
The only theory I have, is those errors that happens even without the Addon Manager loaded, will become more serious when the Addon Manager is loaded, so they appear as proper errors with a crash, but they might be the original cause of the problem.
As I've said, the Addon Manager is unchanged, except for allowing to run with the Hotfix, because nothing of the things that needs to be updated has actually changed so, if there was an issue with the Addon Manager, it should have happened with plain 2.5 too, while all these reports are coming only after the Hotfix.
The issue is, I also get crashes with the Addon Manager loaded, but they are entirely random. Once I can run with no issue for quite a while, the next I get a crash within a minute. Perhaps there's some kind of conflict between VC++ libraries, but I just can't trace it to anything.
Again, the case is NOT considered closed or solved, it's just that right now I don't have any idea, other than the Hotfix doesn't seem to be very stable.