I'm aware of an incident a few years (not a 737) where the towbar ended up in almost the same position.
In that case the error was spotted and the aircraft stopped before being struck by the towbar.
The sequence was, after completing the push:
Bar disconnected from tug.
Tug moves forward to leave room to disconnected the bar from nose gear.
Bar is disconnected from nose gear.
Bar is pulled forward ready to re-attach to the tug
Before doing this the headset person removes bypass pin & unplug headset.
As the push had been longer than normal it was too far for the headset person to walk back to stand.
Headset person entered tug as passenger and they returned to stand where pin/flag were displayed.
Inexplicably they forgot to reattach the bar to the tug before driving off.
It was thought that the longer non standard push caused a distraction and they were uncomfortably exposed being a considerable distance from the stand with another section of twy to cross before reaching safety.
They were eager to return quickly from an area they felt exposed/unsafe.
As the aircraft started to move it commenced a left turn towards the adjacent runway holding point.
The error was spotted and the aircraft stopped just before the bar would have struck the right engine.
I suspect something similar may well have happened here.
I note that the towbar head is under the engine, it would seem unlikely it was still attached to the nose gear at the time of txy?
I'd guess either left in error or not correctly attached to tug when it moved off.
Last edited by 42psi; 20th Dec 2021 at 20:31.