You haven't said:
- Which airplane you used. If it's not a default airplane, clearly indicate the 3rd party airplane add-on used.
- Which airport and gate you used. If it's not a default scenery, clearly indicate the 3rd party scenery add-on used.
And, your screenshot is not very clear. It only shows a reversed truck, but it's not possible to understand from the screenshot when this happened.
If it happened before the pushback started, it might be a problem with the airplane configuration file. Which is why, I asked to identify the airplane used.
If it happened during of the pushback, the most common cause it's a scenery error, like overlapping/unconnected/orphaned/missing nodes in the 3rd party scenery you are using. Which is why, I asked which airport and gate you used and if it's not a default scenery, clearly indicate the 3rd party scenery add-on used.
