This is an intermittent problem.

A page contains several versions of an attachment uploaded by different authors. Occasionally, when:

a) a new comment is added to the attachment
b) a new version of the attachment is uploaded
c) when the attachment is moved

ALL historical versions have their last modifier changed to user who was behind one of the above. The last modification date is also changed to the latest update.

This is a problem because you lost track of who made changes to the attachment. This is really important to some organisations.