Hey Sheila,
This happens anytime you change the length of the bone in edit mode after you have already added a stretch-to constraint.
Sometimes it can be really obvious – as the problem can get exacerbated the further down the hierarchy it goes.
But sometimes it can be really small and be just enough to cause you to scratch your head for a really long time.
The key to to remember that this can happen when you move things in edit mode.
Of course, it wasn’t an issue in the demo I made for you the other week where I rotated the whole arm. I won’t tell you why but I will ask you to think about the reason.
(hint: Read this whole comment again from the start if it doesn’t jump out at you)
