Order of related issues is reverted after save.

Steps to reproduce...

1. Edit or create a new issue.
2. Add at least 3 issues and make sure they are listed in ascending order.
3. Save the issue.
4. Edit the issue again.

Expected result:

The order of the issues should be retained as entered by the user.

Actual result:

The order of the issues is reverted to descending.

PS: I'm not sure whether this is entirely a d.o D7 upgrade thing or if it should be solved in a more generic manner/place. If so, please feel free to move to the appropriate queue.