I'm not sure what you mean by synchronized but I'll presume you are the owner of both. Projects in Atlas are your projects. Listing an Epic from Jira only tells the people you share the updates with where the work is being done. The Epic itself doesn't update the Atlas project.
That said, you might want to follow this post from Atlassian about the upcoming changes. Atlas itself is going away, sort of. Atlas Group articles/Atlas is evolving
TBH, this article, while I read it about 5 times is very vague and I don't really know what to expect.
Are there any more details which I can follow up on?
But, maybe I will describe the actual problem:
- create Jira Epic
- create Atlas Project based on that specific Epic
From there on, I expect that changes I make in Atlas will be automatically synchronized to Jira Epic - or is this wrong expectation and I'm using it wrong?
Update - it seems now the due dates are synchronized, but I would expect other fields to be updated automatically as well
