As a user of Aha! / Gitlab integration, I would like to assign a milestone or any other object created in Aha! and propagated to Gitlab be removed in both tools if it is deleted in Aha, so that the users on both sides of the integration have consistent information.
Thank you for your idea. We intentionally do not delete any records from integrated systems when you delete a record in Aha!. If you really want the linked record to be deleted too you will need to do that manually in the other system.
The reason is very simple: there is too much risk of users inadvertently deleting data, especially when they are just getting started. We hope you understand.