When dragging a task on Maniphest it appears properly, but after a page refresh it is shown in wrong order.
This is the behaviour (all in the same priority)
If moved up, it will be moved n+1
If moved to the top, it will be placed at the end of the current priority list.
If moved one position down, it won't appear as moved.
If moved down more than one position, it will move n-1 positions
Changing priorities works as expected.
I've updated the code at the latest current revision and it is not fixed.
This started to happen with code introduced this month. Probably between March 1st, 2015 and March 7th, 2015.
Let me know if I can provide more information to troubleshoot this issue.