How to reproduce the issue

Step by step

Fill ressource (yes, double s) in the search field right below the Tiki logo and click Go

Pay attention carefully!
First you see the listpages with 2 pages listed and the message « Found "ressource" in 2 pages. »
So far, so good but it does not stay long and then you get the table to be reloaded with all pages in the list.
The message « Found "ressource" in 2 pages. » stays there ironically.

The issue is not there if tablesorter is disabled

Which you can confirm here: tiki-admin.php?page=features&cookietab=2&highlight=feature_jquery_tablesorter