If you can reproduce this bug, then I think it is a big one.
- Have a Project A with a Milestone 1 subproject.
- Get some tasks associated to Milestone 1.
- Go to Project A workboard in Natural view.
- Change the sorting of tasks in the Milestone 1 column (without moving the tasks out of that column).
Nothing happens to the tasks themselves. They are still associated to Milestone 1.
Tasks moved within the Milestone 1 column are now associated with Project A, not anymore with Milestone 1. Even if in the Project 1 workboard they still appear in the Milestone 1 column. A little mess.
It happened in Wikimedia Phabricator:
- Developer-Relations team workboard, see "Apr-Jun-2016" milestone column with 49 tasks: https://phabricator.wikimedia.org/project/view/33/
- "Developer-Relations Apr-Jun-2016" has only 12 tasks, the only 12 tasks I didn't touch at the milestone column from the Developer-Relations workboard.
- An example of a task dragged within the milestone column. "Qgil edited projects, added Developer-Relations; removed Developer-Relations (Apr-Jun-2016)." https://phabricator.wikimedia.org/T131914#2259439
I discovered this problem precisely the day that I repositioned dozens of tasks in two workboards... So much for tidy workboards. :) :/ :(