How to reproduce:
Add an ordered list (i found it with that but probably with unordered too), make the post, go to edit post after posting, TinyMCE adds spaces and unnecessary <ol> tags (if you look in the html view).
A bigger issue than this appears when using the spoiler tag, editing the post breaks the whole template, making the list go outside the posts and forums divs like the following snippet (try to post and repost the edit without touching anything else):
[ list=1 ][ * ]Old Spice Taste
[ spoiler ]Cryburied Bot
sdfsdfsdf
sdgfdsg[ /spoiler ]
[ * ]sadasfsa
Old Spice Taste
[ spoiler ]Cryburied Bot
sdfsdfsdf
sdgfdsg[ /spoiler ]
[ /list ]
(remove spaces between the brackets, it was getting formatted here)