After sending Ricoh UK quote from page 90 of the manual:
How to achieve correct exposure with aperture ring not set to A:
1. set the mode dial to M
2. set the aperture ring to desired aperture
3. press green button, the correct shutter speed will be set
4. If the correct exposure cannot be achieved adjust ISO sensitivity
I got another reply today:
Thank you for contacting Ricoh Imaging.
We have forwarded your case to our product specialists for investigation. They will test the camera in the same situation as you described.
After the testing is done we will get back to you with an advice. If you are in need of further assistance, please respond to this email or call our technical support center.
Sincerely,
Ricoh Imaging Technical Support
Now I'm waiting for the product specialist take on the problem
.