Thanks for your reply and the tip. We started a support case directly with Phase One.
We are using a 645DF with a P65+ with Capture One Pro ver. 6.2.2. on a iMac 27, 2.8Ghz Intel Core i5, 12 Gb RAM, Mac OS X ver. 10.6.8.
We saw it first with .IIQ files (P65+) and confirmed it with .CR2 (1DsIII) files, on different computers. It was with a low Keystone adjustment (Amount 100%, Aspect 2%).
To make it more visible, here is a snapshot (at 200%) with Keystone adjustment (Amount 100%, Aspect 5%). Look at the glasses. It is quite noticeable at a zoom of 100% depending on the type of photos, especially with diagonal lines. Increase the Aspect slider and the effect gets even more visible (horizontal lines). Use negative Aspect values and it produce weird vertical lines.
The same photos processed a couple of weeks ago using CO ver. 6.2.0 or 6.2.1 don't have this problem. Seems to be specific with CO version 6.2.2.
In our case, we deal mostly with fashion and this type of adjustment are not necessary (applied in that case by user error). Resetting this adjustment got rid of the problem. Might be a different story for arquitectural photographers. Just trying to help the community and avoid others a headache.
Can you or anyone confirm this?