beagle-thunderbird and tmp files?

Hello,

I am running beagle-thunderbird 0.3.8-13 on my FC10 system.
I experienced loads (10's of thousands) of tmp files in /tmp containing 
headers of old email messages after installing beagle-thunderbird.

Are these files coming from beagle-thunderbird?
If so:
Why are there so many?
Why aren't they cleaned up?
They interfered with the working of the system!

if not: What could be the source?
How could I find out?

Please let me know.

Thanks,
Udo