I updated PSXT to v12.5.5 yesterday, 04JAN and have been getting InvalidParameter in the MSFS Crash log. I have not had any issues with GSX and have ran everything the same. The only change was PSXT update. This is using 2020.
Though, It seems it could be linked to GSX based on a forum post. However, I am able to inject for quite some time before the CTD occurs.