Getting creatures unstuck

[temnix]

Creatures can get stuck on terrain after having been through "No collision detection." I thought I had a reliable way to prevent this - put a delayed spell on them with instant "Teleport field," range 0. (Putting a delayed Teleport field on them directly would return them to the starting point instead.) This used to be enough to get them off the invisible hook, and it worked every time I tried it. I don't know what's changed now, maybe I'm not doing it right, but the trick isn't working any more. I have to give a real range to the effect, and obviously I can't make it a range that would be noticed, because why is the character jumping around? But also the distance is random within that range. If I set the range at, say, 10, I sometimes get no movement at all and therefore no liberation. If I set it at something greater, it still may not work. So here I'm casting for information on how to get creatures unstuck.