Wrong direction of rotation

Where does Rotax say no more than one rotation in direction opposite normal?  I have searched the manuals and can’t find this limitation.

It is taught in all the classes and has been on many forums for decades. If you do this too much you WILL ruin your sprag clutch and have to pull the engine and back of the engine off to replace it. This is no different than having "prop kick back" on startups and trashing the sprag. I don't even go one whole turn back. I just do maybe a quarter to a half turn.