These two icons for the image fit to box have always been the wrong way round. The left snaps image to the height and the right to the width. Try it.
I don't think so. The icons in the Control panel do exactly what the tool tips say.
Just tested that with InDesign 2021 version 16.3.0 on Windows 10.
From left to right from my German InDesign:
"Rahmen proportional füllen" (Fill frame proportionally).
"Inhalt proportional anpassen" (Fit contents proportionally).
( ACP )
The left one fills frame in both directions, even if the whole image does not show. The right one fits the image to the frame, leaving white space if the image proportions don't match the frame proportions.
OK, I know all that. Do you think the top icon on your examples shows an image fitting both sides of a box?
It is the icons that are confusing, they look like fit to width and fit to height.
They do not mean 'snap to height or width' at all, they mean different 'fit/fill' options... And that is exactly what they do.
So I guess you misunderstood the meaning of that icons?
Correct they are very badly designed, don't you think?