Hi,
This does not seem to matter too much, not sure, but if I reply to the same email twice I get:
error in process filter: Error 70: /home/xxx/mailbox//cur/1438677852.M414675P17005Q0R1ce38bb62ec6c347.mnemonic:2,RS already exists
The email is sent alright it appears, but I should check if the first reply gets overwritten or the second not saved. Anyhow, it seems to me like a bug.