The motor stays in "revved up" mode

It happened occasionally last season even when I was not cutting high grass, and went back to normal on its own. This season it started in revved up speed and has not changed back to normal the two times I have mowed my small lawn.

Any help would be appreciated

Update: Contacted the Ryobi help desk tech who diagnosed it as a "controller"

problem which would be fixed with the replacement of the electronic circuit board.