Can you provide a bit more context? From your question, it is a bit tricky to figure exactly where the problem may be occurring.
It sounds like something isn’t showing up in some sort of reports based on this:
Can you share more on how those reports are affected? What APIs, if any, are you currently using? Can you share screenshots of how/where you’re indicating the Parent Link of an Epic? Can you show/share more on what you expect to be happening and what is actually happening?
I’ve also just published this guide on asking a good question. Check it out and see if there aren’t some other ideas in there on ways you can provide us more context to help get things sorted.