QGIS "effects" not displaying in print composer

Question

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.

Any advice?

I'm using QGIS 2.18.5.

enter image description here

• HDunn: I can't recreate your problem on 2.18.10, the outer glow on an SVG symbol appears fine in the print composer. Try this in a fresh .qgs file and see how it goes, maybe there's some problem with the current one.
• rhys: Thanks for the suggestion. Does not seem to be a problem in a fresh .qgs file. Unfortunately, there's probably several hours worth of work for me to reload layers, styles and recreate lost layouts in a new project file. Is there anything else I can try first? EDIT: closing the layer, reopening and re-creating the style has worked.
• HDunn: You don't need to redo all the symbology for all the layers. In a fresh qgis project: Layers -> Embed Layers and Groups -> Browse to your current project file (QGIS_170318.qgs) -> Open. Don't forget to save as a new qgs file.

Answer 1

This error can be solved by closing the affected layer, re-opening, and re-creating the style. Still unsure why the issue occurs.

• LaughU: Did you try to first copy the style -> close layer -> reopen -> past style? with this approach, you don't need to recreate the style (if it works)