I have used various, from a Roeders that would move less than 0.002mm week to week. That was the nuts. It had full cooling circuit running through the casting, and also on the drives it's self along with spindle growth comp. I've also used stuff that's moved the same as your seeing. The first 5x I worked on was a Mikron UPC600, when we first got it we found the same as yourself if not more. We had major issues trying to blend toolpaths in from different tool vectors. We initially thought it to be a machine problem, then the supplier paid to have it put in a temperature controlled tent for 2 weeks as a trial, and that helped the issue straightaway. It still wasn't perfect but it helped massively. If you're mould making and trying to blend 2 tool paths in on an impression it's always going to be a battle. I also found that varying tool diameters caused blending issues as well.
Its a difficult one as it's not really feasible to reset your spin centres numerous times a day.