What those dials do is scale the bones, and regrettably they do that very poorly.  The stock tongue is modeled in a curled up pose, and the bones all have to be bent to straighten it out and then scaled.  The TongueLength dial is capped at 1, and when you override the limit and make it longer, the mesh goes nuts when bent (and you only have three bones to work with anyway).

Edit: huh, just checked and it's not curled up in zero pose after all, I wonder if that changed since the earlier releases of V4.  I hadn't bothered with the stock tongue in quite a long time.

 

Duh, Markschum I completely misunderstood what you were suggesting, that's a very good suggestion.

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