I have this problem as well. All of my five skeletons started moving like this, and did not correct themselves when I went out of town or when I resummoned them.
I also encountered this bug. All of a sudden the skeletons were teleporting around a few times every second as I was walking, instead of smoothly moving. I replicated it several times, and it appears to occur after turning in some quest and going through the quest dialog.
One way I was able to fix was open the skeleton book and change the upgrade to another one - it made all skeletons disappear, and upon summoning them from scratch the issue was fixed.
I also tried to swap the skeleton summon skill with another skill on my bar, in order to make them disappear, but when I placed the skeleton summon button back on the bar and summon them the issue was still present.
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