I've noticed that since 2015 came out, blend modes on adjustment layers no longer have any effect. I hope this is a bug and that the feature hasn't actually been taken out. I have tested this on multiple windows machines all running After Effects CC2015.
Tested it by putting a "Fast Blur" effect on an adjustment layer, and setting the layer blend mode to "Add" usually, this would give you a simple cheap to render glow.
Does anyone know if this is also happening on Mac?