Thanks for your reply!

Actually, I rather often use(d) the combination <p> & </p> within <li> & </li>, also in the Steemit editor, so I really wonder if that could be the reason for my problems with this post, but I will check out what happens, when I replace all <p> & </p> within lists by <br> or <br/> or <br />. :)

What I also wonder about, is, why the appearance of the post itself looks exactly as intended in my blog, but problems only arise when I try to edit it?

While contemplating about that, I think it would be nice to have the possibility to write 'test posts', not to trigger all the auto votes when just testing anything.

I will try to edit the old post and check how the editor preview looks like when changing the formatting according to your suggestion.