Q: Upon flattening my image, my Layer Effects change appearance, or disappear altogether. What is going on?
A: You should
always examine your effects and filters at 100% zoom. At any other zoom level, the preview image will just be an approximation. At 100% zoom, there should be no difference between layered and flattened image.
very rare occasions, changes can occur on flattening, probably due to exotic blend modes. If you experience a visual change upon flattening at 100% zoom, please report so on the list, so any bugs can be worked out. Such changes are extremely rare, and 99.99% of reports of visual changes are due to 'wrong' zoom setting.