I probably don't mean the same wobble that others mean. I don't have a precise measurement of what I feel, other than that Matias switches don't feel clean and smooth. When I got my Quiet Pro, the switches felt like they were juddering as you pressed them.
I don't know what the cause is. They share the one-armed bandit contact design as simplified Alps but they feel distinctly worse, although simplified Alps also has a double-bump curve that messes up the tactility, a lot like black Alps switches in the AT101W/102W. It's nothing to do with simplification; I have a clone keyboard next to me (KPT KPT-84) and the switches in that (USw LABI01) are smooth, and once you pass the tactile point, the rest of the force curve is linear without any grinding or extraneous bumps. The simplified Alps design (which might be a copy of one of the clones, as the one-armed bandit design appears to long-predate simplified Alps) seems to be a really poor idea, and the Matias switch is a copy of an already bad design (one which I think was the Himake cheap range, rated for 5 M instead of 10 M cycles, but without research assistance, I won't be able to gather the data I need on those switches).
Blue Alps is just exceptionally smooth. It might be that both Cherry and Alps changed their plastics around the same time, since there's a widely-held belief that old Cherry MX switches were also smoother.
There's enough spare switches out that someone with access to the right kind of laboratory could get all the materials analysed. The same could also be applied to all the other ultra-smooth switches to see if they all share the same plastics.