Sorting Issue on ticket number

Hi Everyone,

osTicket version 1.9.7

PHP Version 5.6

While sorting the on ticket number (Closed & Open) it does not sorted out correctly, Some random tickets are displayed in between.  Screen shoot is attached. If we export it, Excel is able to sort it correctly.

Even if we sort tickets in descending order but still it is displayed in ascending order.

Regards, Ronak.