Reconstruct dying with bus error

[Zachariah Mully]

Howdy all-
	I'm running into many mailboxes moved from 2.2.13 to 2.4.12 which 
reconstruct barfs on with a 'Bus error'. I'm running reconstruct as such :
# find /var/spool/cyrus/mail2 -maxdepth 3 -mindepth 3 -type d | sed 
s:/var/spool/cyrus/mail2/[a-z]/::g | xargs -n 1 reconstruct

It continues to barf on all subsequent runs of reconstruct. If I resync 
it from the 2.2.13 server, and run reconstruct on just that mailbox, it 
works fine.

So:

mail:~# find /var/spool/cyrus/mail2 -maxdepth 3 -mindepth 3 -type d | 
sed s:/var/spool/cyrus/mail2/[a-z]/::g | xargs -n 1 reconstruct
...
...
user.gbiz.Sent uid 58 future modseq 2 found
xargs: reconstruct: terminated by signal 7
mail:~# reconstruct user/gbiz/Sent
user.gbiz.Sent uid 58 future modseq 2 found
Bus error

[Resync with 2.2.13 server]

mail:~# reconstruct user/gbiz/Sent
user/gbiz/Sent
mail:~#

Any hints on WTF is going on here? It's going to be a PITA if I have to 
manually sync/reconstruct/sync/reconstruct/... to get some sanity on the 
2.4.12.

Thanks,
Z