Can a QuickTime video be partially cached?

We deliver QuickTime video to clients as progressive downloads (not
streamed) via the Akamai network.

There is one client that is consistently able to view only half of one
specific video - the progress bar then stops. This behavior can be
repeated on several computers within the building. Other delivered
video does not have the same issue and this behavior is not happening
at other client facilities.

Assuming that the client has some sort of proxy server or other caching
mechanism, is it possible that only a portion of this particular
QuickTime file is cached, and therefore everyone in that building is
only getting the partially downloaded, cached content?