After update from 6.5.1(build 17834) to 6.5.3(build 17985) - Each build the Agent do a clear checkout

Before this update, each checkout was just one update like  "Will use fast SVN update", that take just 20min­, however after the update, all the build do a clear checkout you can check in the Build Log:

[13:47:31]: Updating sources: agent side checkout... (1h:36m:43s)

[13:47:31]: [Updating sources: agent side checkout...] Will perform clean checkout. Reason: Agent doesn't have any version of the project sources

The problem to do a complete checkout takes almost 4 hours, and in 4 attempt just one is capable to finish all the other 3 fail for the follow reason:

Failed to delete empty directory: C:\TeamCitySWCheckoutAUT\tags\5.9.3\ClientSetup\.svn

Note: Each time is a different file...

After one successful build if you try to run again the build that is responsible to do the chechout, a clean checkout start instead a "Will use fast SVN update".

Today, I reverted to the version 6.5.1 (build 17834), and works correctly, I was wandering if i need to change some configuration or this is an bug ?

Thanks,

Gabriel Aphonso