Actually, although it should not be, the effect could be explained with a bad / too small guard-band setting.I don't know anything about Warp3D, but if it isn't the guardband problem
Somehow I doubt that because I can't imagine someone would set the guard-band to such a small value. This would cause almost any game to not work properly (unless you work around that by "patching" your geometry accordingly), at least at decent render-target-resolutions.