PPro2014 Game Developer SR5 but also previous SR from October 2014.

I have a mirror on a wall.  When characters are close to it they are reflected properly. When they get about 20 feet away they invert and become enlarged (Upside Down and bigger). I haven't figured out where the inversion point is or if it changes suddenly or gradually.

So, basically, what I see is characters close to a mirror, then table and chairs along the back wall hanging upside down from the ceiling and really zoomed in.

As far as I can tell the mirror mesh is straight, but the mesh is my higher suspect. I know this is probably not enough information for a diagnosis, but wanted to see if anyone had experienced a Poser bug before I started trying to figure out what setting, distance, mesh, etc. might be causing the problem. 

Anyone hear or see anything like this?

you could replace it with poser plane prop, which has correct normals.

also, show yer mat room settings.

What you describe is possible with a concave geometry mirror, or a flat one with a carefully designed normal map applied. Since you didn't mention a normal map, your surface must not be flat.

If the inversion happens around 20 feet away then the radius of curvature is 20 feet. A mirror about 4 feet in height with an indentation of about 1.3 inches would produce such an effect.

Two good suggestions and a method towards diagnosis. Sorry for the delay; I'm not always here.

  It is a set that I bought. The mirror looks flat, but may not be. Not sure what is meant by ' a carefully designed normal map applied.'

 I did 'borrow' the reflections material from a mirror that was working on another set so I tend to suspect the mesh here.

I'll see if I can get a screen capt of the mat room settings. I'm wondering now if I have a spherical reflection map applied someplace and it is inverting?

Also I will see if I can separate out the mirror mesh - or turn it off independently - and replace it with a poser plane prop.

any poly has a normal ~ is the way its pointing ( is an average of the vertex normals ) they can be altered but its not for the faint hearted lol and I don't think poser can do it

"Not sure what is meant by ' a carefully designed normal map applied.'"

I was explaining what the circumstances could be. If I had told you the only way to get the effect you described was a curved (not flat) mirror, then I would have told a lie. There are two ways to get the effect. A curved mirror is most likely, but it is possible to do this also with a perfectly flat mirror, if you have a way to alter the normals. A normal map (or bump map but these differ only in the assembly - they do the same thing) can distort the surface of an otherwise completely flat geometry.

Here is a demonstration - the square mirror is completely flat. I am sure because I made it. It is a single 4-sided polygon, with all four vertices in the same plane. The reflections are distorted by a carefully designed normal map. In particular, it is a parabolic normal map - it mimics the curvature of a parabolic mirror.

I'm in no way suggesting this is your situation. I included the possibility of altered normals to prevent the potential exhibition of pedantry that might have ensued if I'd made the inaccurate claim that the only possibility is a curved mirror.

Note: Your mirror geometry may indeed be flat, and the curve is being added because the edges are welded to other non-coplanar polygons and you enabled smoothing. Smoothing bends polygons into curves to make organic surfaces smooth. If you have smoothing on for the mirror, turn it off.

Here is the same mirror with the alteration of normals removed.