Depending on your account setup you may occasionally see fewer than 10 results per page even when they are 10 or more search results returned.

You will see links to the additional pages to see the remaining results.

This is caused by the use of alias articles on the account. Each alias article is returned as a separate result. ScreenSteps aggregates the duplicate results into a single result with links to each manual that result belongs in under the search result.

So, even though the search returned 10 results for the first page, they have been de-duplicated and then given links to the context of each article.

There currently is not a workaround for this besides not using aliases on your account.

Related:

What are article aliases?