I’m Dorian, software engineer at Algolia and I’m going to help you solve your problem as best I can.
If I understand your problem correctly, when using the distinct feature with query rules you still see a duplicate result between the distinct search results and the promoted result.
Yes, unfortunately, it is a known issue to us that query rules do not play along well with distinct.
As a workaround, I would create a new index with deduplicated results manually and apply query rules on that index. What do you think of this proposition?
I hope this can help you and don’t hesitate to ask further questions.