Hello Jane
You shouldn't need to do anything special. Is there a pattern that you can see? If you update the comment on a PI attribute after adding the subtypes, do the changes get propagated?
For testing, you could create an extended attribute that checks the comment is the same for an inherited attribute as it is in the parent attribute:
Here's the criterion you need:
and the extended attribute (which will only be populated for inherited attributes):
You can see the result in the attribute properties:
In this case, the value is False because I manually updated the inherited attribute comment.