Internal hyperlinks stop working randomly in Storyline 360

Hello Adrian, 

Happy to help!

I tried to recreate this behavior in a new project file but I encountered no issues with either the functionality of the hyperlinks or its hover state. My test slide looks like this: 

And this Review 360 link demonstrates the behavior. Since I wasn't able to replicate the behavior, would you be willing to share a copy of your project file here or in private by opening a support case so we can take a closer look at what's happening? We'll delete it when we're done testing!