Status "S" in Subversion

At some point all files in my working copy got marked with "S" symbol as shown below:

$ svn st
M    S   AclController.php
     S   InstallationController.php
     S   CustomerController.php
     S   RedirController.php
     S   IndexController.php
     S   LoginController.php
     S   OrderController.php
     S   ProductController.php
     S   SelfInstallController.php
     S   SelfcareController.php

Interestingly it occurs only int this particular working copy - when I checkout the project to new directory, it does not show the "S" marks.

How to get rid of this annoying "S" symbols? It significantly decreases clarity of WC status.

Update: I do switch from time to time using standard svn switch syntax. It was never causing this "S" symbol to appear until recently. The command used to switch was:

svn switch svn+ssh://xxxxxx/subversion/xxxxxxx/releases/1.0.16 .

Is there any way I can clear the "S" flag?