Plugged into shore power and starting the truck...?

No, you're fine. There are too many safeties and limitations involved to do any damage.
* The factory wiring from the TC to the truck can't pass enough current to do any damage, at least when compared to a stout set of jumper cables.
* The truck has a fuse on that circuit, and the highest I've ever heard of is 40amp, most are 25-30amp. Your converter is likely 45 amp.
* The circuit is de-energized in the "Start" and "Accessory" positions, so it can't make the connection during start up.