In my opinion and how I understand layouts, I feel like it’s a bug.
This is a very similar situation, but with the ‘See All’ option on inline lists.
In general I follow the rule that detail layouts are tied to sheets but only at a sub-level below a top level tab or ‘link to screen’ button. Another way to look at it is that the details of a list item will always follow the same layout throughout the app as that layout becomes part of that sheet.
List Relations and ‘See All’ are kind of a gray area, so I’m not sure what the right answer is. Since it’s still a list view I wouldn’t expect the design of it to carry through to other ‘See All’ or List Relation view, but it’s still at a sub-ish level from the top screen, so it’s probably attaching the list design to the sheet as well.
Like I said, it feels wrong to me and very similar to the other post where the user would set the layout of the ‘See All’ list, but that layout would carry through to all other lists on the screen that used the same sheet, but were all intended to show different information.