There are also some ideas here:
Coincidentally, one of the solutions for exit code 11 was to delete a video track. But I suspect that having more than one video track is not the problem itself.
If an export fails inconsistently, and at a different time for each try, then we typically ends up being a resource problem (memory or disk). If an export fails consistently at the same spot, then there is usually a problem occurring with a specific filter or transition. In those cases, the user can delete the filter or transition that occurs around the time of the failure and then recreate it.