Just a guess, It could be made on purpose to speed up the render time in Poser 12 using Superfly and the reason why it never has been addressed to be fixed. It is known that Increasing the Dpi will cause a drastic increase of render time no matter the size, resizing actually does not Increase the Dpi as larger size will just keep the 72dpi and will render faster no matter what. Most users use a setting of 90 ++ dpi to get a good result basically 150-300 is the most used setting. So my thought is that it is not a bug it rather seems to be the render speed up key, or at least a part of it. Else it would of been addressed already a while ago.