A search page sometimes displays less than 15 results per page (page size 15, total results> 15)

Preconditions:

1. Login to Forum JCommune.
2. Click the link "Profile" in the right top corner and set Page size parameter for 15 posts. 
3. Go to the forum's main page.

Steps to reproduce:

1. Enter a word in the search field, for example: "test", "testing", "action" and others. Click Enter.
2. Scroll through the search pages and calculate the number of results per page.

Actual result: Any of the pages displays a different number of results, less than 15. Sometimes there are pages with no results. 

Expected result:  There are more than 15 search results. The user should see a page with 15 search results and a pagination bar. A smaller number of search results can only be on the last page, if the number is not a multiple of 15.