Hey,
I stumbled across a small bug by accident, I didn't find any previous reports.
When you're at a gate and request pushback but abort the pushback for whatever reason the planes shakes a second (freeze / unfreeze I suppose, nothing to worry) and then the tug starts driving to the aircraft and gets connected, also pushback has been aborted.
When you select "Continue pushback" another tug is spawned and when you click abort again this tug also is driving to the aircraft and getting connected.
I stopped trying with 3 connected tugs and 3 wingwalkers.
Cheers Phil