Steps to reproduce the issue

When I include in search module in my Joomla website, the pagination is not working as expected. Two issues :

1. If a search a word it shows that it found 10 records and when I change the display # filter to 5, it says "Total: 9 results found." which is strange.

2. Secondly after changing the display # filter to 5 and navigate to the next page, it doesn't display the rest of the records, its empty.

Interesting thing is that when I change the display # filter to 10, it displays all the records as expected in single page.

Expected result

Pagination feature of search module should display rest of the records in the next page after clicking. on the "next" button

Actual result

Changing the display # filter to 5 and navigate to the next page, it doesn't display the rest of the records, its empty.

System information (as much as possible)

PHP Built On : Windows Server 2016 AMD64
Database Version : 5.7.9
Database Collation : utf8_general_ci
Database Connection Collation : utf8mb4_general_ci
PHP Version : 7.1.11
Web Server : Microsoft-IIS/10.0
WebServer to PHP Interface : cgi-fcgi
Joomla! Version : Joomla! 3.8.3 Stable [ Amani ] 12-December-2017 15:00 GMT
Joomla! Platform Version : Joomla Platform 13.1.0 Stable [ Curiosity ] 24-Apr-2013 00:00 GMT
User Agent : Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:57.0) Gecko/20100101 Firefox/57.0

Additional comments

New installation of Joomla 3.8.3 doesn't shows this behavior. How to track why search pagination is failing ?