Layer Styles - Recurring Multiple Strokes

I created an image with 10 layers and applied a layer style, bevel and emboss and stroke, to each layer. As I added layers, strokes were repeated so for example there were 8 stroke entries for the 8th layer, 9 for the 9th etc. The plus option for strokes also failed to expand. I closed the image and even rebooted PS. When I opened an entirely unrelated image the layer styles still retained the multiple stroke entries. How can I delete multiple stroke entries in layer styles?