Hi Damon,
I think it is not a bug, I think you have two different relationship 1:N from Account to Case.
The CRM by default only have 1 I think.
To check, can you go to the Account, check the relationship, 1:N Relationship
If you see to different relationship, then it is different relationship actually, maybe one is Case to Account as Customer, another one is Case to Account as Vendor, both are using 1:N relationship from Account to Case, but they are different.
If you notice in the first picture, there are 2 Contact and Account relationships, but they are two different relationship and different field as well.
If you want to hide one of them, you can go to the relationship you want to hide
and change the display setting to do not display (it will hide the navigation pane), or you can also change to custom label.
By default, it uses Plural Names.
Then, save and publish it.
Then, you can check in the Form Editor, the Navigation.
You can see the Contact appears duplicate.
And the Case is now using the Custom Label
You can double click and see that the duplicate contact is actually two different relationship.
You can also Hide it or Change the Custom Label as well.
If you want to keep both different relationship in the Form Navigation but don't want to make your Customer confused, then better you change the Label.
And here is the result if you change the Custom label.
So, this is not a bug :)
And you can change your display properties.
Hope this helps!
Thank you.
