what is going on when bzr push shows 'Copying signature texts' progress bar?

[Alexander Belchenko]

Anytime I'm trying to do initial push to my server bialix.com via bzr+ssh
I see phase 'Copying signature texts' for most of the operation time.
Why it took so long? Or may be bzr is not sitting in this phase actually, but
another code is not updating progress bar correctly?
Both local and remote repository is shared repo in pack format.

AFAICT, after packs is landing progress bar behaves much worse than with knits.
Often it shows 0/0 phase etc.