I'm having an issue where effects created under Layer Properties -> Style -> Draw Effects/Customise Effects do not display in the print composer window.
See screenshot below - in the main QGIS window I have an outer glow effect applied to the workings svg symbol. However, once a print composer is created, with a map displaying that area, the effect disappears, just leaving the standard black svg icon.
I'm sure I've previously had maps in the print composer honouring custom effects, but I may be mistaken.
I'm using QGIS 2.18.5.