[Dovecot] Error: Master request X not found

[Jordi Moles]

*Hi, I've been getting the following error from time to time since i 
started to use dovecot more than one year ago:

dovecot: May 07 19:57:24 Error: auth(default): Master request 
88729.43523 not found

I haven't stopped upgrading dovecot with the hope that this would be a 
bug and would be fixed some day, but with v1.0.0, i keep getting the 
same error.

It just happens from time to time. Some of the users of my system 
complain about not being able to get to see their mails, and it is 
always at the time when this error is logged.

Surfing through many forums, i came across with a cause that many people 
point to:

"client closed connection at the exact same time master was logging it in"

i don't know if this is what happens to my system, to be honest, i don't 
have a clue how to check that, i just would like to know if somebody has 
come up with a solution for this problem, as it seems many people are 
still trying to face it.

thank you.
***