What causes syncs off messages?

[Christoph Höger <choeger@xxxxxxxxxxxxxxx>]

Hi,

what exactly causes offlineimap to sync a message again? When I open
evolution on my maildir (asides from confusing mutt) the next time I run
offlineimap, it will download lots of messages again, overwriting old
ones but not changing something.

Since I think evolution has some bugs in its maildir support, I wanted
to know what could trigger those downloads.

regards

Christoph