Strange date changes to doc files on rpmbuild/mock

[Pavel Alexeev (aka Pahan-Hubbitus)]

Randall J. Berry wrote:
> 	Hello,
> I am building a package and everything works just fine except for one
> strange anomaly that I can't figure out. When the package builds it
> changes the doc files (COPYING, README, INSTALL) dates to December 2009
> from their original date of December 2008. Both rpmbuild and mock are
> doing this. I've never noticed this before and it's only happening to
> this one package.
> 
> It has a very simple spec file and no specific copy methods are used to
> copy these files other than the %doc macro itself. Anyone have a clue
> why this is happening?

Strange...
Do this happened on koji build too?