Canon 85mm f 1.8 aperture not working.

[Michael Winokur]

I have an older Canon 85 mm f1.8 (gold band) lens. I've tried repeatedly to mount it on my Scarlet. When I mount it I hear the aperture moving. I can set the aperture on Scarlet but after a few seconds the aperture value begins to flash or change from 1.8 back to whatever it's set for. I found a Reduser post about re-seating the lens and rebooting but that didn't help. I double checked the lens on a Canon camera and the aperture moves smoothly without sticking. Is there a chance this lens isn't in the Scarlet's firmware? I'm not having this problem with my 70-200 2.8 IS or Tokina 11-16.

Thanks for your input.

-Michael