There are unwanted line breaks in the middle of this reply: https://en.wikipedia.org/w/index.php?title=Talk:Investigations_into_the_origin_of_COVID-19&diff=1008382587&oldid=1008382503
The message looked normal when I clicked the 'Reply' button to post it.
There are unwanted line breaks in this article: https://en.wikipedia.org/w/index.php?title=Investigations_into_the_origin_of_COVID-19&diff=prev&oldid=1008213302
The paragraph looked normal when I saved the page.
There are unwanted line breaks in the middle of this reply: https://en.wikipedia.org/w/index.php?title=Talk:Investigations_into_the_origin_of_COVID-19&diff=1008382587&oldid=1008382503
Presumably, the complaint is about this diff?
So, those additional list items (at the same level) in the middle of that reply looks like something that the Discussion Tools inserted. I cannot think of a scenario where Parsoid would on its own add new list items. But, we should see if there is way to reproduce this in isolation and see what HTML that DT sends back Parsoid.
As for the second one, again, we should see if we can reproduce it and see what HTML is posted to Parsoid.
Presumably, the complaint is about this diff?
I think it's more-specifically about this diff -- the other one just shows the undoing of the specific error.
It's weird, because we're not sure what scenario would result in a correct visual preview, but output HTML that results in the italics being pushed to a newline in the wikitext.
From Slack, the comment was made that "I can kind-of reproduce that when using the API directly, by just passing html parameter without a wrapping <p> tag. I have no idea how to cause that when using the normal editing surface though."
After merging that patch, I can't reproduce any more by following those steps. This is probably fixed.
Looks like there are still cases where this happens: https://en.wikivoyage.org/w/index.php?title=Wikivoyage:Travellers%27_pub&oldid=prev&diff=4586094
This is clearly not happening regularly, and I can't reproduce it, but it seems likely related to wrapper paragraph logic. We did change this recently to fix a similar bug (T348467), but there is an instance form 2022 that pre-dates this.
@JTannerWMF, do you remember anything specific about the way you composed the message, e.g. copying and pasting from an external editor like GDocs?