Sometimes my scheduled transactions end up being for a slightly different amount to that in the schedule. When I match the real and scheduled transactions up when importing, I end up with an unbalanced transaction (see attachment). I would expect both accounts invloved in the transaction to be updated with the real amount, or at least something to highlight the issue.
I could reproduce the bug by following your steps. Thanks, that's a very interesting bug. A transaction should never be in an unbalanced state like that unless it's a multi-currency transaction. The "other side" of the transaction should have followed the amount change imposed by the importation.
(from [b8da68dcea10]) [#351 state:fixed] Balance splits after a bound txn import.