webmail not always using canonical address

[jeffw]

I just noticed that one of our trial users replied to a message I sent him, and the From header used the store-specific address (uid@zstore.usg.tufts.edu) rather than the canonical address (first.last@tufts.edu).

Subsequent test mail seems to do the right thing.

What would cause this?

Thanks!

[jeffw]

We're still seeing this. Anyone have an idea why it's sometimes doing this?