Green pictures

I had indoor 'studio styled' setup, shooting with a canon 7d, 17-40 and one off camera flash. Out of the 400 photos I took, about 5 of them turns out to be green. This had this exact setup on 2 other occasions earlier this month and this problem never occurred. What could be the cause for the green pictures?

green completely or with green tint?

It would help if you post examples, complete with Exif/settings, both of one showing the problem and one taken with the same gear and lighting that doesn't show the problem.

I don't have the images any more. But it looks like this. It may be called green tint.

https://www.photoshopg​urus.com …elp-please-green-tint-jpg

I shot everything in manual mode (iso800, f5.6, 1/125) with manual power flash output.

Looks like WB jumping. Hve no ide why, though.

Is there any other lighting in there?

Without seeing actual photographs, it is hard to say what is going on. That said, it is likely that you have a light source other than your studio lighting that is flickering. Most likely there is an old florescent tube type light causing your problem. If you are using auto white balance, the camera may be choosing the wrong white balance due to the timing of when it meters the white balance.

There were some weak banquet hall lighting.

I will be surprise if it is WB jumping. I was using flash wb.

The setup is one off camera flash bouncing off a white umbrella. I have used this same setup a few weeks ago and shot over 400 pictures, no issues.