Maybe there is some bug that counts the shot at the end of a rotation towards target as still moving? I noticed that it's usually those that the JT misses. Like when you order it to attack, it rotates the vehicles then once the vehicle is in range it shoots and misses. I dont't think it's a coincidence either. I sometimes used the JT for casual fun games before the last changes and it was insane how often it would miss. The "new" JT did the same when I played today. Even on ranges around 20-30 or sometimes even lower than that.
IIRC, Stugs were losing their spotting scope ability when rotating to shoot. I think rotation does count as movement for anything without a turret. I haven't tried a spotting scope on a Stug in awhile so I can't say for certain.