Changing function of envelope wipes out points

Hi all,

I have an existing recording with an envelope that I've saved to handle the speed of a Leslie speaker. Somehow the function of the envelope got changed to "bypass" rather than "speed". If I go into where the envelope function is defined and change it to "speed", all of the points get reset to zero. Does anyone know how to avoid this and why it's happening?

I hope my description was clear!

Thanks,
Steve

Changing function of envelope wipes out points