Easy fix if its just the connector. It might have been a counterfeit connector. This is why some people cut the crappy generic connectors off, they are the first fault to look at even if they look fine. Those phase wires are so small (guessing 14awg?), resistance is higher in small diameter wire (higher gauge) so length wouldnt matter too much unless its very excessive, an extra foot I dont think would matter much for low power systems. As an example I am known to wrap excessive throttle wires around the handle bars and frame to save time in doing it the right way just to get riding.
You might have popped a fet, I'd snip the bad wire off and hard wire it asap to see if its still operational rather then grabbing a meter to check each fet. You could have also overloaded the connector with to much power, the solder joints of the connector could have been very bad and hidden from view.
I was looking for the issue in the pics of the controller pcb. If that would have been your case, then I would have looked at routing of the phase wires from the pcb to the exit at the case, or looked at a pcb component failure that cause the component to overheat that might have had a wire touching it.
Overlapping phase wires for example, just like inside a hub, you dont want them overlapping, you want them far apart because they heat up with all those amps.
That connector, is small. The pins of the connector are close together. If the connector took a hard hit, could have crushed the casing of the connector forcing the phase pins of the connector to touch. Overheat and pop fet.
I have used those, unplugging them and plugging them in for a flat, that same style of connector had the housing misformed from not properly disconnecting both sides in a uniform manner. Think about when your riding and your tired, maybe cold and maybe you disconnect the connector a little off a few too many times. Then it could have taken a hit from the bike falling, or getting hit by a rock or tree. Could be anything. Replace with good connectors like XT's, PP's, rc 4mm+ barrels, molex for low power stuff (I have never seen high power molex at my local store, I wanted to try molex for 50a.) you can even hard wire the connections if you need it done asap. Just dont hard wire the battery
If you hard wire the phases, make enough slack to replace a flat, not much is needed. I talk about hubs.
Another possible failure if it was inside the controller was a phase was touching a hot fet. You ever feel your controller after a big hill? Touch the backing plate side of the outside of the controller where the fets mount to. Some controllers have an extra piece of metal in there, with that white dielectric I assume it is. I had one where I loosened the fet bolts to fix cap and a pc of metal fell into the controller case, it was hard to get it back in place.
Those are just some other scenerios that could have occured, but a bad connector is a bad connector. And that connector is not stout, might feel stout to your fingers. I know in tools they reinforce the plastics with glass fiber for strength, that costs a lot extra money. I highly doubt they used good quality plastic for the housing.
Another thing I hated about those connectors is trying align the marks to connect them together. The arrow is small and black, the housing is black. End up twisting it around in frustration shoving them together and the pins catching and deforming as you twist to connect it.
