@Sanbie
Hi, I have that problem that a MATpose is turning something in the legs also with your "Hooded Wintercoat Set". B.t.w. very fine clothing ...

I have looked to the MATposes but found no reason for the posing mismatch.

But looking to the CR2 I found 2 strange things.

First in both "Goal"-Props are a embedded geometrie of an ball (and also a extended shader-tree, I think).  I have never seen in any model to date that the "goal"-prop does include something.
Ok, I am not realy sure for what the "Goal"-props are realy necessary, so I was astonished to find something like a geometrie in that. I don't know how you rigged the models, but I rather sure that this was not by your intension, or am I wrong. Might be this could make some strange effects ???

Second thing is that most of your models come with a PMD-File. Though I not a friend of this, but it's ok.  But I find also all morph geometries in the CR2-File.
I have read and checked that this is a specific bug with Poser 7 SR 3. P7SR3 isn't erasing the geometrie information from the CR2 when building its PMD file. Poser 6 and Poser 7 up to SR2 are doing this correct.
Loading the Wintercoat with Poser 6 and saving it under a new name with building PMD made a different CR2 file as expacted. But there are not only diferences by the morph geometrie but also differences to some other parameters, e.g. KD-Colors etc.
So to store the same model with P6 and P7SR3 and then examine the CR2's diferences might bring some ideas why there are that misbehavior with MATposes.

@SeanMartin
Hair props often goes flying off although correctly parented then using pose files PZ2.
Mostly it's cause the people creating the pose have forgotten NOT to save the hair with the figures parameters. If such a pose file is used and the hair is a other than that at the pose creation (that should happen often ...) the hair reacts to the wrong parameters of the file.

Greatings Jo