I think I found a Bug in Version 6.4.13 (git hash: b8c6e0d).
When I select continue numbering form previous… in a numbered list, the entry gets a bullet list instead of the next number of the previous numbered list.
I attached a small screencast to explain what I mean https://help.egroupware.org/uploads/default/original/2X/d/d981ff1f020166da31b7153f15d828e95d87d674.mp4
You have a bullet list in front of it in your example. The circle that is not filled in:
So the continues there, but in the first level, so a filled-in bullet point.
In my test, it continues at that point with a numbered bullet list.
what I was trying to accomplish is to have a numbered list and at some point of the list an additional bullets list inserted (se here after 2.dgdg) :
This seems to be possible ONLY if you first enter also the next number following the entry where you want to insert the bullets (e.g. 3. dggd) :
and then go back, enter an additional line inbetween:
and finally convert that line into a bullet list and push it one level lower:
This behavior seems to be the same also in LibreOffice 18.104.22.168, so I guess its not a Bug.
Thanks again and Merry Christmas!