1. Edit a topic with two paragraphs or more.
2. There is a whitespace before the second (and later) paragraphs' beginning even when the user didn't add it.
See https://www.mediawiki.org/wiki/Topic:Se6p2ic73417viw1 for example. I didn't add a space before the "More again." but it's there when you try to edit.
Merging in T94372 -- probably the same issue:
As in the case of TABs (T93851), these `<nowiki>` tags are not wanted, and Flow should not be adding them:
* https://pt.wikipedia.org/w/index.php?title=T%C3%B3pico:Segoxqgdyct4l8f6&action=compare-post-revisions&topic_newRevision=segpnrtx6c48dipl
* https://pt.wikipedia.org/w/index.php?title=T%C3%B3pico:Segsdt3rteotwijl&action=compare-post-revisions&topic_newRevision=seh4f4stv64b7hl3
The first one was breaking the list syntax, and the second one the link syntax.