evolution-2.3.3.1: local mail delivery agent dies silently after time

["Joseph E. Sacco, Ph.D." <joseph_sacco comcast net>]

A "local mail" delivery agent used to retrieve local mail from an mbox
formatted spool into folders managed by Evolution dies silently after
some time period, typically over night. 

An artifact of this failure is Evolution can no longer be shutdown gracefully.
Clicking "File->Quit" initiates a shutdown sequence that hangs. 

After kill off all remaining Evolution processes and restarting Evolution,
all is "well". The local mail delivery agent once again works as expected.

Speculation:
        A connection to a pipe or socket has been lost. Killing off and restarting all
        evolution processes re-establishes that connection.

A bug report, #308296, has been filed.

-Joseph

-- 
joseph_sacco [at] comcast [dot] net