a few of my team have had this happen:
start to enter a new issue, fill in several fields, realize they are in the wrong project, change project via the jump to a project pulldown and have all of their typing removed. I suggested they go to the correct project first. Or complete the issue then do a move.

But I was thinking that, like the functionality to edit common fields across multiple issues, this workflow could be made to remember the common fields between issues in the two projects. Or at a minimum the subject and description.