Jira: "Relative of" vs "Related to"
In Jira, linking items together is easy and useful.
For example, you can clone an issue easily: Create issue 100, clone it to 101. 100 then shows "this issue has a clone: 101" and 101 then shows "this issue is a clone: 100"
Similarly, you can mark issue 201 as being duplicate of 200 (reverse is 200 is duplicated by 201), and there are a few other link types.
My question is around the use of related tickets. One side of the relationship is marked "This issue is related to ..." and the other side says "This issue is a relative of ...".
How does your dev team define those two items? It wouldn't matter much except the display is different, making the link types slightly different and it just looks like they are different when one issue is "a relative of" a few other issues, but also is "related to" some others....
Answer
In JIRA, links are directed, i.e. not symmetrical. One part of the link is the "source", with one role, like "duplicates", the other is the "target" with another role - "is duplicate of".
When you have a symmetrical link semantics, like issues related to each other, this just does not work well. You can name both roles equally ("is related to" -- "is related to"), and this will work to some extent. You can expect "is related to" appear twice where you select a link type, for example.
In your JIRA configration, this probably lead administrators to define the roles for the "related" link type differently. But I guess this is more a bug than a feature, and you can safely ignore the differences between two names of the same relationship.