angle limit on servos are not mirrored with mirror symmetry
how to reproduce
place any rotational servo on a part in mirror symetry
click on part and disable full rotation
set angle limit to only allow positive or negative values
set target angel to be non zero
when loading the craft one of the servos will rotate violently until it is within the inverse of the angle limit
example set angle limit from 45 to 60 degrees
upon loading the craft the "other" servo will rotate to within -45 and -60 degrees
the target angle is mirrored "correctly" so that the parts rotate the same way (although one is rotation clockwise and the other anticlockwise)
the angle limit is mirrored "wrong" and is in the same direction for both servos.
the rotation is usually strong enough to tear your ship apart och catapult it away.
what you cant see between these two images is the rapid rotation.
for greater angles the parts just rip it self loose.