If it has gotten to a jury, it has already taken a significant amount of time and resources from the district and the teacher.

That moves it to an earlier point where it is dismissed much sooner. If it is not dismissed before discovery (and why would it be?), then that too takes a lot of resources from the district and the teacher.

So it then moves to a "the district settles early so they don't have to deal with the lawsuit" and it becomes a "sue the district and get a payday since they'll settle."

To get it moved to a "this can be dismissed as a matter of law rather than a matter of fact", then the corresponding laws need to be in place to protect the teacher.