Done a bit of digging and found this line in the coautl log file. Found gsx.cfg file at C:\Users\<username>\AppData\Roaming\Virtuali/Airplanes\JF_146_300\gsx.cfg
error in gsx.cfg, section 'exit1', key 'embeddedstair': argument should be six numbers (two xyz points) or 0, with an optional expression. this is the section from my gsx.cfg
[exit1]
pos = -1.69 8.35 -0.60 3.00
code = (L:EXT_Door_pax_1L, number) 0 !=
name = L1 Door
embeddedStair = -2.19 8.38 -0.60 -3.71 8.46 -2.12 (L:EXT_Door_stairs, bool)