Support service confirmed they know about this bug and are fixing it.
As for me, it stopped reproducing in my account yesterday. So I hope that now it’s already fixed.
That is scary, since Asana tasks are pretty much critical in many cases. I did notice that this happens sometimes when you change the due date from today the today view to later.
You are probably seeing the result of the updated My Tasks that Asana is just now rolling out. In lieu of the built-in auto-promotion, you can now create your own rules to define your own customized auto-promotion behavior.
For more on this new My Tasks, see:
I also recommend you read this article for additional help:
I’ve been having the same frustrations, but it looks like @Phil_Seeman covered this in the Medium post he linked to earlier. Because My Tasks is just another board, you will need to use the Ctrl/Cmd+Shift+Up and Ctrl/Cmd+Shift+Down shortcuts to move tasks between Today/Upcoming/Later.