Can you confirm that you have experienced the problem on different computers? (In case you have two OS on the same hardware)
Have you experienced the issue on different image documents? What are the properties of the documents? i.e. pixel size, bit depth?
Something I should have asked before... How are you using Lighting Effects? What is your workflow and what are you trying to achieve? Is it a sort of basic vignette, or are you using alpha channels, layer modes and going for a bass relief effect? Why I ask is because the latter can cause offsets rather like Displacement Maps.