I looked at what you reported under the assumption that your “numbered paragraph” means an element of a “numbered list”.
Indeed when you hit the Enter key twice Writer promotes the numbered paragraph but not only 1 level but to an unnumbered paragraph.
This make sense if you list looks like:
This makes in my opinion no sense if the list looks like:
. 1. blalkjdfa
. 2. second level sample paragrah
- first level sample paragraph
When you hit Enter twice while the cursor is in “2. second level sample paragraph” the result should be like “2. first level sample paragraph”
I made the test using LibO 188.8.131.52 on XP.
Please feel free to place an enhancement request at: https://www.libreoffice.org/get-help/bug/?enhancement=yes
You can make a link to this question.
It would be nice if you report the bug number of the request here again to allow others to add comments.