Comment 18 for bug 1068921

So, the first broken nightly appears to be https://ftp.mozilla.org/pub/mozilla.org/thunderbird/nightly/2012/06/2012-06-20-03-02-01-comm-central/thunderbird-16.0a1.en-US.linux-x86_64.tar.bz2

(https://ftp.mozilla.org/pub/mozilla.org/thunderbird/nightly/2012/06/2012-06-19-03-02-01-comm-central/thunderbird-16.0a1.en-US.linux-x86_64.tar.bz2 works ok)

I've also tracked it down to a specific message too. There seems to be 2 issues at play:
1) That the message is saved offline at all, as it is larger than the 50kB limit
2) When it is downloaded it never seems to get marked as available offline, so it is downloaded repeatedly every time the folder is updated (and ends up in the mbox file multiple times)