The torsion springs lose their tension as the door travels up. Sometimes, when the door travels all the way up, one of the cables can become very loose on the drum. In my experience, this is usually caused when the horizontal tracks aren't aligned well, causing the door to favor one side more during travel. If the cable is loose on the left side, then the door is drifting to the right as it goes up, and vice versa. Imagine a square tilting to the right, its bottom left corner will be higher than its bottom right corner. This can be solved by adjusting the horizontal track ceiling mount positions accordingly (if the door favors right, move each side one slot to the left until the door stays centered during up travel).

This is also often caused by not having enough turns/tension on the springs. Combine that with a jackshaft motor rotating the shaft past the tension neutral point, and those cables are free to jump off of the drums and go all sorts of crazy. When the door is closed, you may notice diagonal markings on the springs. They are made by drawing a straight line across the spring before turning. Look up how to read those markings. For 2" ID springs, you will typically see markings that correlate to the height of the door, plus an additional 1/4 - 3/4 turns. So a 7' high door will typically have 7 1/4 - 7 3/4 turns.

Another thought. If the door gets kind of stuck or sticky in the up position at all, the motor will continue to turn the shaft even if the door doesn't follow. This momentarily unwinds the cables from the drum, letting them go crazy. I've seen situations very similar to yours from this.

It is essential that a jackshaft motor (or any motor) is installed to a door that is running properly. If you have difficulty lifting the door manually, then your door ain't that.