(process:5301): GLib-CRITICAL **: g_source_unref_internal: assertion 'source ! = NULL' failed

I got this error at the end of an akonadictl stop - just wondered if its of 
interest to any dev. (full message list below)
For the record, I had just done a "akonadictl stop", "rm -r .local/share/
akonadi",  "akonadictl start" and waited for a while for it to recreate its 
structures etc, eventually went back into Kontact, checked an email, still got 
the "retrieving folders.." on an old email, closed kontact, did a "stop" in 
order to do a "start, fsck, vacuum" and got the following.

bingmybong@thesite:~/.local/share> Qt has caught an exception thrown from an 
event handler. Throwing exceptions from an event handler is not supported in 
Qt.
You must not let any exception whatsoever propagate through Qt code.
If that is not possible, in Qt 5 you must at least reimplement
QCoreApplication::notify() and catch all exceptions there.

(process:5301): GLib-CRITICAL **: g_source_unref_internal: assertion 'source !
= NULL' failed
QWaitCondition: mutex destroy failure: Device or resource busy
chainup()
org.kde.pim.akonadicontrol: Application 'akonadiserver' exited normally...

-- all messages after teh akonadictl stop --

akonadictl stop
org.kde.pim.pop3resource: Settings(0xbe32e0)
bingmybong@thesite:~/.local/share> Settings(0x262c2b0)
Settings(0x13ab330)
Settings(0x25d52f0)
org.kde.pim.akonadiserver: "Cannot connect to agent instance with identifier 
'akonadi_maildir_resource_0', error message: ''"
org.kde.pim.akonadiserver: "Cannot connect to agent instance with identifier 
'akonadi_maildir_resource_0', error message: ''"
"Unable to fetch item from backend (collection -1) : Unable to retrieve item 
from resource: Message recipient disconnected from message bus without 
replying"
org.kde.pim.akonadiserver: "Cannot connect to agent instance with identifier 
'akonadi_imap_resource_0', error message: ''"
org.kde.pim.akonadiserver: "Cannot connect to agent instance with identifier 
'akonadi_imap_resource_0', error message: ''"
org.kde.pim.akonadiserver: "Cannot connect to agent instance with identifier 
'akonadi_imap_resource_0', error message: ''"
org.kde.pim.akonadicontrol: ProcessControl: Application "/usr/bin/
akonadi_imap_resource" stopped unexpectedly ( "Process crashed" )
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_imap_resource' 
crashed. No restart!
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_imap_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_mailfilter_agent' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/
akonadi_newmailnotifier_agent' exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_maildir_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_birthdays_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_pop3_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_pop3_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_akonotes_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_pop3_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/
akonadi_followupreminder_agent' exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_pop3_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_migration_agent' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_archivemail_agent' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_contacts_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_ical_resource' 
exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/
akonadi_maildispatcher_agent' exited normally...
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_sendlater_agent' 
exited normally...
org.kde.pim.akonadicontrol: ProcessControl: Application "/usr/bin/
akonadi_indexing_agent" stopped unexpectedly ( "Process crashed" )
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_indexing_agent' 
crashed. No restart!
org.kde.pim.akonadicontrol: Application '/usr/bin/akonadi_notes_agent' exited 
normally...

bingmybong@thesite:~/.local/share> akonadictl stop
bingmybong@thesite:~/.local/share> Qt has caught an exception thrown from an 
event 
handler. Throwing
exceptions from an event handler is not supported in Qt.
You must not let any exception whatsoever propagate through Qt code.
If that is not possible, in Qt 5 you must at least reimplement
QCoreApplication::notify() and catch all exceptions there.


(process:5301): GLib-CRITICAL **: g_source_unref_internal: assertion 'source !
= NULL' failed
QWaitCondition: mutex destroy failure: Device or resource busy
chainup()
org.kde.pim.akonadicontrol: Application 'akonadiserver' exited normally...

-- 
opensuse:tumbleweed:20170419
Qt: 5.7.1
KDE Frameworks: 5.32.0
KDE Plasma: 5.9.4
kwin 5.9.4
kmail2 5.4.3
akonadiserver 5.4.3
Kernel:  4.10.9-1-default
Nouveau:  1.0.14_2.1