Trigger for forward marker not working

Hi everyone, I am currently building a slide with several layers and have included a forward marker on each layer which, when clicked, brings the user to the next layer. I've set all the layers up the same way and all are functioning properly except one. When I preview the slide, the forward marker on the second last layer doesn't work. I have tried deleting the trigger and inserting it again, I've tried copying and pasting a marker from another layer and nothing seems to be working. I can't find anything on the actual layer that may be preventing it from working so I'm hoping someone could take a look and perhaps see something I may be missing. I've attached the .story file; the layer in question is layer 4 and I'm trying to get the forward marker to jump to layer 4.1 when clicked.