Well, it appears every time at every airport now, since the last live update.
The message is :
couatl v3.1 (build 3510)
panic log started on Thu Jul 14 15:03:10 2016
problem raised by addon <unknown>
Traceback (most recent call last):
File "couatl\common\fsm.py", line 61, in switchToState
File "couatl\GSX\assistanceServices\__init__.py", line 743, in enter
File "couatl\common\criticalsection.py", line 23, in _synchronized
File "couatl\GSX\assistanceServices\__init__.py", line 141, in requestVehicles
File "couatl\GSX\__init__.py", line 810, in prepareGate
File "couatl\GSX\__init__.py", line 749, in removeOtherSimobjects
File "couatl\GSX\__init__.py", line 773, in _removeSimobjectsAtGate
AttributeError: 'NoneType' object has no attribute 'createdByCouatl'
{'Airport': 'KDEN', 'Requested assistance services at': 'Gate P 14', 'User Pos': (39.85401057316478, -104.66814011375604, 1656.87 m, 1.50542 m, 263.7300246951754)}