OT: digital recording mystery

["petr" <petr@tryi.com>]

Because of colaboration with a friend of mine on a recording project,
we recorded and exchanged a track in this sequence: digital
multitrack --> pc --> burned cd (wav) --> pc --> minidisc --> pc -->
burned cd --> pc --> multitrack.

When I wanted to sync the newly updated recording (new track in left
chanel and original in right) I found that the new version (both the
original recording and the new one) is somewhat faster, about 0.4
second in four minutes.  It was all done via digital connection
(spdif) and in 44,100 Hz.  Can anyone explain the mystery how the
recording could get faster, or provide some hint/insight?

Thanks,

petr