Take a look to the following example:
  <div style="display: inline-block; border: solid thick; height: min-content;">
    foobar
  </div>

In legacy layout the height of the DIV is 0px, however it should be big enough to fit "foobar".
This works fine in LayoutNG though.

Note that min-content on block axis should behave as auto, but that's a different bug (see issue #902863).