Could be a bug but I'm also new and could be doing something wrong: Why are some ideas being linked as a "Linked issue" and others being linked as a "Delivery ticket". Both are JPD ideas and they look pretty identical to me and in both instances I used the + button there in the Linked Issues section in the Overview tab. Not sure what other info is useful to help troubleshoot, let me know and I'm happy to supply it.
It's because I was using the wrong link relationship / dependency.
