artifacts appear when v.6 file is processed in v.7

Last week we photographed a blue Porsche in the studio using Capture One Pro 6.4.4.

In the interim, we downloaded a copy of the new Capture One Pro 7. In reading the accompanying materials, it said that the new software would afford better results.

We took one of the capture files that was captured in 6.4.4 and brought it into 7 to compare. We set all parameters to neutral or 0 on both sets of software. Our intention was to do a direct comparison.

When we processed the file in 7, we got a series of vertical artifacts that were not in the original 6.4.4 file. We processed the file again in 7 and the artifacts went away. We processed again in 7 and the artifacts reappeared. We processed again in 7 and they reappeared again. We never saw the artifact in 6.4.4.

When we were able to achieve a clean processed file in 7, we did see an improvement in overall quality.
We are very concerned about the problem with 7, as we are currently working on a very large project that could use the improved file quality. I need to quickly decide if I am going to reprocess all of the files captured in the past two weeks. The project resumes next week and I need to know if I should capture in 6.4.4 or 7.

I am using the latest MacBook Pro, 15" Retina Display machine with 2.6 GHz Intel Core I7 processor and 16 GB of 1600 MHz DDR3 RAM.