Asymetric display of an info box when two paragraphs are added inside

To reproduce:

• in a document add an info macro (warning, success, error have the same issue)
• inside this macro, add a paragraph, save, view. The spacing of the box is symetric wrt content of the box
• edit, add a second paragraph in the box (by leaving an empty line between the two blocks of text. Save, view.

Expected result:

• Symetric spacing wrt content of the box

Actual result:

• on the bottom of the box there is slighly more whitespace than on the top of the box.

See the screenshots.

The cause for this seems to be the way paragraphs (p elements) are spaced wrt surrounding elements:

• on colibri there used to be a margin of 0.5em on top and 0.5em on bottom
• on flamingo there is only one spacing, on the bottom, of 10px

This does not reproduce for only one paragraph because when there is only one paragraph in an infobox no p element is added.