All good so far.
However, when a question that was closed as duplicate and its duplicates list has been edited is reopened, the duplicates list is not cleared. This means that if the question is then closed again as a duplicate, it will show the list of duplicates instead of starting from a clean slate.
This can be seen in the revisions list of the above question:
And then the question is closed as duplicate of all those in the list:
In this specific case I agreed with the original closure so the list is still good, but in other cases, question might be wrongly closed as duplicate of other questions, reopened, closed as duplicate of the actual source, but still be duplicate of that wrong list of questions.
I really think that reopening should clear that list.