With switching the alternate geometry is either there or isn't, if it isn't it wouldn't show in wireframe. Sounds more like an actor display style or material issue, or even a normals issue. With little to go on, and not knowing how the tail is modeled,

I would select that tail part and try changing display styles via object:display style

Or look at what the materials are for that part

Or, if its created using one sided planes, similar to hair, try checking normals forward in the material.

All guesses...