I can't tell why, but the following is "in effect" on en.WikiVoyage.org for some reason but the same is not needed(?) nor found nor in effect on a comparable site like test2.wikipedia.org as far as I can tell....

.section {
    clear: both;
    padding: 0;
    margin: 0;
}

The offending attribute and value causing that specifically is clear:both found -- at the minimum -- in both MediaWiki:Gadget-ListingEditor.css & MediaWiki:Gadget-ListingEditor2.css.

And I guess the "conflict" only revealed itself now thanks in part to the recent changes "ending" the Beta option testing Visual Editor in one's User: preferences and having it load by "default" on qualified projects instead.

A temp change to clear:left resolved the rendering to match test2 easily enough in case that matters somehow.