When you saved the animated pose, I suspect that you used the 'Morph Channels' switch. Thus, if the face morph in question was in a zero state when the pose was saved, of course the pose will reset the face morph to zero when applied.

I suggest that you apply the animated pose to the figure, then resave the pose without selecting the 'Morph Channels' option. This will produce a pose that will not affect any of the morphs.

Alternatively you can edit any specific unwanted morphs out of a pz2 using a Poser file editor, eg the free 'CR2 Editor'. If the pose was saved as a p2z (compressed pose), you may need to convert it to a pz2 before you can edit it, depending on which editor you use.