remove the shrinktube and check for youself. (they may have made them longer since I had the problem.)
One of mine broke too a year ago or so . I discovered it when one motor pulsed a lot while flying.
You should be even more concerned over the other bad soldering jobs that stick together, for the time :)
Please check all solder joints as they will probably be almost broken, you can bend these wires only one or twice before they start to break strands of wire next to solder joint. I have found this several time too with many motors (even new ones) Just re-solder and insulate well with new heat shrink into motor base. Good Luck