Ambiguous rendering behavior of first paragraph in a multi column environment

[zopyx]

There is a different rendering behavior of tools for the first line of a paragraph in a multi column environment like here:

https://www.print-css.rocks/lesson/lesson-multi-columns

There has been some discussion here about the rendering behavior in the light of the specs:

pagedjs/pagedjs#7

PagedJS and PDFreactor render according to the specs.
Prince, AH and Weasyprint do have a different opinion on the specs.
Chrome and Firefox also omit the first line with the same code example.