This looks like a bug in the wikitext parser, occuring when you mix the HTML lists, wikitext lists, and HTML tables.

Here's the simplest test case I found that causes the same problem – try pasting this into https://ru.wikipedia.org/wiki/Служебная:Развёртка_шаблонов (Special:ExpandTemplates):

Wikitext	HTML output	Screenshot
P15273 (An Untitled Masterwork) 1 <ul> 2 <li><table><tr><td> 3 test 4 * a 5 * b 6 * c</td></tr></table></li> 7 <li>test</li> 8 </ul>	P15274 (An Untitled Masterwork) 1 <div class="mw-parser-output"><ul> 2 <li><table><tbody><tr><td> 3 <p>test 4 </p> 5 <ul><li>a</li> 6 <li>b</li> 7 <li>c</li></ul></td></tr></tbody></table></li></ul> 8 <li>test</li> 9 </div>

Luckily, there is a simple workaround – just add a line break at the end of the last wikitext list item:

Wikitext	HTML output	Screenshot
P15275 (An Untitled Masterwork) 1 <ul> 2 <li><table><tr><td> 3 test 4 * a 5 * b 6 * c 7 </td></tr></table></li> 8 <li>test</li> 9 </ul>	P15276 (An Untitled Masterwork) 1 <div class="mw-parser-output"><ul> 2 <li><table><tbody><tr><td> 3 <p>test 4 </p> 5 <ul><li>a</li> 6 <li>b</li> 7 <li>c</li></ul> 8 </td></tr></tbody></table></li> 9 <li>test</li> 10 </ul></div>

You can probably achieve that on https://ru.wikipedia.org/wiki/MediaWiki:Protectedpagetext and https://ru.wikipedia.org/wiki/MediaWiki:Blockedtext by adding <nowiki/> on a separate line after the template parameters, to ensure that the line break is not removed.

Parsoid doesn't have this bug, so one less thing to worry about there.

In T279912#6991344, @matmarex wrote:

You can probably achieve that on https://ru.wikipedia.org/wiki/MediaWiki:Protectedpagetext and https://ru.wikipedia.org/wiki/MediaWiki:Blockedtext by adding <nowiki/> on a separate line after the template parameters, to ensure that the line break is not removed.

Ok, we will do it, thanks :)

In T279912#6991344, @matmarex wrote:

You can probably achieve that on https://ru.wikipedia.org/wiki/MediaWiki:Protectedpagetext and https://ru.wikipedia.org/wiki/MediaWiki:Blockedtext by adding <nowiki/> on a separate line after the template parameters, to ensure that the line break is not removed.

Does not work :(

I'm sorry, I forgot about this task, and only ran into it today while cleaning up my notifications.

I was able to fix the problem on-wiki with this edit: https://ru.wikipedia.org/w/index.php?title=MediaWiki:Protectedpagetext&diff=115033821&oldid=113622335&diffmode=source (I'm a global interface editor). Sorry for not explaining it clearly enough!

Before:
After: