Scaling of markers in graphs no longer works properly. Per the online documentation at https://helpx.adobe.com/illustrator/using/graphs.html:

“The design is scaled so that the backmost rectangle in the design is the same size as the default square marker on the line or scatter graph.”

This is how it used to work. Now it scales the markers down to fit in the default marker’s bounding box, which creates absurdly small results (screenshot attached, showing the size that should be generated per the documentation versus what actually happens). I've tried this multiple times and always get the same incorrect result.

Illustrator 29.2.1 on MacOS 15.3.1