Troubleshooting Timeline13 Center Line Animation Issue

Timeline13 - center line not animating down on scroll Hey all, quick question, I'm using Timeline13 in a website I'm building, however the progress animation for the center line isn't working, only the dots work. I've applied z-index-2 to the section above the timeline section and applied a background colour as advised - this hasn't made any difference. If I put the timeline section onto an empty page it works fine. All thoughts appreciated.