Sample .blend here. Sorry, I imagine this is a fairly straightforward / dumb problem. I built a test normal map in MindTex from a greyscale pixel art height map. Testing the resultant map in Blender Cycles gives me some weird rendering issues, where identical (as far as I can tell) point lights at different sides of the column appear to render very different casts of light and shadow on individual faces.
The UV appears to be correct, the normalmap should be fine (it's a very simple map and MindTex has proven to be a useful tool in the past). If I disconnect the map in the material nodes, the problem fixes itself.
...What on earth is going on?
Appreciate any time you can give this. Looking forward to a solution...!
--Rev