Yeah, those shields look same as mine.
I'll check soldering once again, however I am far from being expert and to my eyes in looks ok. In fact, I got same reply about checking contacts on stackexchange.
However, the fact that 0.1uF capacitor makes it run much longer than 0.68uF still makes me think that problem might be not in contacts. I don't have enough knowledge in electronics and cannot explaint what is going on there. Also, motor works fine if I touch motor terminals with multimeter, which probably (probably) rules out version about bad contacts.
Do you think it might have something to do with noice generated by motor and soldering +2 0.1uF capacitors to the motor might help?