This is actually an easy experiment to do. So I thought I would prove to myself that my ZM C-Sonnar (which I like) did not have this problem.
I put the lens on an R-D1 on a tripod angled down toward a spread-out newspaper. Camera was 9 inches above the table, focusing distance 0.9 m set on the lens. I used the Leica 1.25x magnifier held up to the viewfinder to position the paper so I knew just where the rangefinder plane of focus was. Then I took a sequence of images at apertures 1.5, 2, 2.8, 4, 5.6 without touching anything but the aperture ring.
Yes, the lens focuses about 2 cm closer to the camera at aperture 1.5 than at 2.8. You can see the answers right on the camera’s LCD. There seems to be little movement in the plane of focus after that, but it’s hard to estimate since so much of the paper is in focus at the smaller apertures.
A Zeiss pre-war Contax mount 50mm Sonnar at 0.9 m had about the same amount of focus shift. Incidentally, the plane of focus for the lens differed from the rangefinder plane by about 3 inches with this adapter, made from a Contax helicoid. I think Roland made a similar observation on one of these adapters.
Canon 50/1.2, at 3.5 feet, about the same focus shift between apertures 1.4 and 2.8. I think I remember this is a double Gauss design and not a Sonnar.
Noctilux 50/1.0 at 1.0 m, similar focus shift from 1.4 to 2.8. Puts confirms this for this lens in his Lens Compendium.
Summilux 75/1.4 at 0.9 m, aperture 1.4 to 2.8, about the same shift as for the other lenses.
I don’t have the lenses you would think would be corrected for this (modern 50 Summilux ASPH, Summicron, ZM Planar, etc) and would urge people to try this with their own lenses. It takes about 3 minutes.
For my own R-D1 + ZM C-Sonnar combination the rangefinder and lens agreed on the same plane of focus at aperture 2.8 or 4. I wouldn’t trust my uncalibrated refurb rangefinder as a gold standard here. But comments on Zeiss’ bulletin seem to indicate Zeiss has calibrated the lens for correct focus at smaller apertures. Puts says the Noctilux cam is calibrated for the wider apertures, which would be my choice. But it’s clear one has to make a choice, because by aperture f/2 the line of newsprint that was in focus at f/1.5 is no longer sharp for me with this lens – which I still like a lot.