When exporting from illustrator SS 2015.3 to .png, the appearance of the layer is lost, has anyone come across this?

Question

Adobe Illustrator

When exporting from illustrator SS 2015.3 to .png, the appearance of the layer is lost. There are a lot of arrows on the layer that are drawn with a line with the stroke turned off, the stroke, trailers and roundings are in the appearance of the layer, and for some reason they disappear when exported to png...