Several users over the past several months have been unable to complete an assigned Milestone when opening it from their Asana inbox or email, receiving a notification that they don’t have permission to complete it. This has happened whether or not the assignee is a collaborator on the parent task (if applicable) and also when the assignee has comment rights in the project. If the assignee opens the task through their My Tasks, by navigating through the project directly, or using a link someone has copied from the task, they are able to complete it.