I've come across this just a few times but it's pretty annoying when it happens. When you select a preset style (ex. "glass"), it creates a layer effect but no properties are set in the effects panel...except opacity. There are about 5 other places to adjust opacity in AD but the one on the effects panel is extremely difficult to find when there is no indication there is "FX" attached to that layer. Hard to explain but it's a very real issue imo. If a layer style is selected and the only thing changing in the actual effects panel is opacity, there should still be an indicator showing "FX" attached to the layer. I can take screenshots to explain further if absolutely necessary but I honestly don't have the time right now.