building a project execute always a scm changelog command

On building a project with build agent enabled if there aren't changed files Continuum always perform a "full" changelog command (svn log -v)
after update working directory command.
The problem is that the lastUpdateDate stored in the buildcontext is overwritten by the scm result of update command even if there are no changed files and after that become null.
I think that with no scm changes lastUpdateDate might not change or might be set at new Date().

Class UpdateWorkingDirectoryAction
method execute
line 128