[Evolution] Bug#619340: evolution: hangs 0% complete on retrieving message, refreshing folder, checking for new mail

[Joysn]

Package: evolution
Version: 3.20.5-1
Followup-For: Bug #619340

Dear Maintainer,

almost everytime when i use Evolution, it runs into the situation that it tries to retrieve the message body, or tries to refresh folders and then it hangs. 
I have setup to mail accounts, one using IMAP/SMTP to my private mail box on a Cyrus/sendmail server, and one using Googles mail service. 
The situation is easy to reproduce when clicking rather fast from one email to the next one, or when deleting a series of emails from the inbox or an folder. 
Evolution then opens a symbol for every "touched" email in the status bar, some of them vanish after a few seconds, but most of them remain there trying to indicate some kind of activity of Evolution, but they never finish. Even when i use the "Cancel current mail operation" button in the tool bar they are not "canceled". And when i try to cancel them via the red button on the icons in the status bar, the label is just changed (cancelling added) but nothing is cancelled.
When i try to close Evolution using the close box on the top right corner of its main window, all widgets and the main menu are greyed and disabled, and after a while Evolution asks me if i want to close it immediately, or if i want to keep waiting. It further states that it can not complete some actions due to network connectivity issues. But there are no issues with the network, at least not to the mail servers which are used by Evolution.


-- System Information:
Debian Release: stretch/sid
  APT prefers unstable
  APT policy: (500, 'unstable')
Architecture: amd64 (x86_64)
Foreign Architectures: i386

Kernel: Linux 4.7.0-1-amd64 (SMP w/8 CPU cores)
Locale: LANG=en_GB.UTF-8, LC_CTYPE=en_GB.UTF-8 (charmap=UTF-8)
Shell: /bin/sh linked to /bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages evolution depends on:
ii  dbus                   1.10.10-1
ii  evolution-common       3.20.5-1
ii  evolution-data-server  3.20.5-1
ii  libc6                  2.24-2
ii  libcamel-1.2-57        3.20.5-1
ii  libclutter-gtk-1.0-0   1.8.0-2
ii  libecal-1.2-19         3.20.5-1
ii  libedataserver-1.2-21  3.20.5-1
ii  libevolution           3.20.5-1
ii  libglib2.0-0           2.49.7-1
ii  libgtk-3-0             3.21.6-1
ii  libical2               2.0.0-0.5+b1
ii  libicu57               57.1-4
ii  libnotify4             0.7.6-2
ii  libsoup2.4-1           2.55.90-1
ii  libwebkitgtk-3.0-0     2.4.11-3
ii  libxml2                2.9.4+dfsg1-2
ii  psmisc                 22.21-2.1+b1

Versions of packages evolution recommends:
ii  bogofilter         1.2.4+dfsg1-8
ii  evolution-plugins  3.20.5-1
ii  yelp               3.21.3-1

Versions of packages evolution suggests:
ii  evolution-ews                   3.20.5-1
pn  evolution-plugins-experimental  <none>
ii  gnupg                           2.1.15-3
ii  network-manager                 1.4.0-3

-- no debconf information