Using the "#" keyboard shortcut (sequence), it's possible to input a list into image caption, which is mangled when turned back into wikitext.
(Resulting page is http://en.wikipedia.beta.wmflabs.org/wiki/Caption_list?action=edit)
Lists are normally disabled in VE's image captions, presumably for this reason.
Neither Parsoid nor the PHP parser handle lists in image captions. Parsoid should probably output HTML tags in wikitext when faced with this problem? But until it does, we shouldn't allow lists there.