Bug hunting support needed: Expo. Override and "modern" vs. "old school" lens

[Walter Schulz]

I need confirmation for a strange bug in Expo. Override function. No hazard involved.
You need an rather old-fashioned lens like 50/1.8 I or II, EF 100/2.8 Macro and a newer one. Any STM should do and so does EF 100/2.8 L IS Macro. Don't know about other lenses fitting the scheme.
Any more recent nightly build would do fine and it doesn't matter if Digic 4 or Digic 5 cam involved.

Steps to reproduce:

- Preparation: Restore ML defaults (you may backup your ML/Settings dir to restore custom settings after test) and shutdown cam. Set lens to MF.

1) Testing "old" lens
- Remove battery, insert battery and powerup cam in photo mode.
- In Canon's QC menu set aperture to lowest number (wide open).
- Open ML menu and access Expo tab. Turn off ExpSim and turn Expo. Override ON.
- Enter LiveView. You may change shutter and ISO to get a proper view in LV. Do NOT change aperture! If you have accidently changed aperture -> Begin from 1) again.
- Press Trashcan button to access ML menu
- Highlight "Aperture" menu item and press set -> You are in Liveview again and "Aperture" menu item is visible in LV.
- Now turn top wheel one notch contra-clockwise. You should see number in "Aperture" changing to highest number available for this lens. And screen goes dark immediately after turning wheel.
- Check aperture blades. They should be properly adjusted to chosen aperture. (If unsure: Leave LV and use DOF preview button to compare).

(You can play around with top wheel if you want. Should do fine. Report if not!)

- Restore ML defaults, shutdown cam and remove battery.

2) Test "new" lens designs.
- Mount lens and insert battery.
- In Canon's QC menu set aperture to lowest number (wide open).
- Open ML menu and access Expo tab. Turn off ExpSim and turn Expo. Override ON.
- Enter LiveView. You may change shutter and ISO to get a proper view in LV. Do NOT change aperture! If you have accidently changed aperture -> Begin from 2 again.
- Press Trashcan button to access ML menu
- Highlight "Aperture" menu item and press set -> You are in Liveview again and "Aperture" menu item is visible in LV.
- Now turn top wheel one notch contra-clockwise. You should see number in "Aperture" changing to highest number available for this lens.

- Now things won't work the way you expect. I think you may see some laggish response or even none after turning the wheel. Try turning wheel until screen goes darker. Maybe you have to force it by half-pressing shutter button (not sure about this one).
After screen goes darker check aperture blades position. You may observe they are not as closed as they should be! You may cross check leaving liveview and using DOF preview button.

Please report back with
- cam used
- lenses used

And don't forget to remove your battery after 2) completed. Menu may behave strange, too. And camera shutdown by power  button is only optional, I suppose. ;-)

Thanks for your time!