Yes this is a known problem. Known, but not WELL known.
I can't remember what order it was but a few years back, people who were locked down in the GR8 had slippage in the Torneos, and people who were locked down in the Torneos had slippage in the GR8. I think it was related to the shape of the heel counter was more biased towards a lower or higher arch (or vice versa, I can't remember). I think people with low arches achieved great lockdown in the GR8 while people with high arches had great lockdown in the Torneos. It may be the total opposite though I can not rememeber the order but thought it was kind of funny at the time.