It seems you have two pushback vehicles ? Nobody ever reported this problem before, and I can't see how this could happen. Please explain exactly what you did, and in which sequence.
Also, clearly identify the scenery:
- Which airport you used. If it's not default, clearly identify which 3rd party scenery you use.
- The name of the AFCAD in use (you can check this with the GSX parking customization page)
- The gate used
- The airplane used. If you configured it, say so.