You aren’t using the correct search syntax.
In the post from @dax the search term offered is
in:likes whereas in your screenshots you’re adding a space and searching for
in: likes - you’re adding a space between the operator and argument.
Spot the difference:
Look at the right hand side - when used correctly
in:likes searches for posts you have liked. It automatically checks that box. When you add the space you’re actually searching for posts which contain the word likes:
Presumably the post with 22 likes doesn’t include the word
likes, so wouldn’t be returned by the search query.
Edit: Confirmed, I just found the topic in question on unstuckpolitics.com. It won’t be returned for a query which it doesn’t match.