[Evolution] occasional authentication problem

[Carl Schaefer <schaefer trilug org>]

I've seen Evolution 3.12.1 occasionally lose the ability to connect to
one of my mail servers (not always the same server, btw) after having
been connected for a while.  When this happens a dialog box appears
asking me to re-enter my password.  Unfortunately the dialog box grabs
the X input, which prevents me from retrieving the password from my
password manager, so I cancel the dialog box.  After this point
Evolution refuses to prompt again for the password; when I try to open a
message on that server, I see log messages like this:

May 06 23:06:33 wot org.gnome.evolution.dataserver.Sources3[758]: AUTH (1394380512 4809 30 wot): Initiated
May 06 23:06:33 wot org.gnome.evolution.dataserver.Sources3[758]: AUTH (1394380512 4809 30 wot): Complete 
(DISMISSED)

The only workaround I've found is to restart Evolution, making sure that
I have the password it needs ready to go.  Toggling offline/online
doesn't work, nor does disabling and re-enabling the relevant account.

I'm using 3.12.1 on an Arch linux system, and Evolution appears to be
using the Gnome keyring to save passwords.  Whatever triggers the
problem initially, it seems to me that Evolution is mishandling
something about the authentication failure.

I don't know what's caused the spontaneous authentication failures, but
I can reproduce the symptoms by changing the password on an account and
then toggling offline/online.

I didn't see any obvious matches in bugzilla, so I'm inclined to create
a new bug report...
Carl