Update of security update hangs for Mojave 10.14.6 I have a Mac mini (late 2014). I did install an SSD disk to increase its performance.
Current Mac Mojave version: 10.14.6
Update: Security update 2020-003 10.14.6
I did this:

Boot my mac using Verbose mode by pressing CMD + V after the booting chime
Choose install update in the update dialog

Please note that I had installed a new SSD drive which might be related to this problem.
What I tried so far:

Unplug all USB devices except the native apple Keyboard

Activate safemode and verbose mode which gave me an error:
  sudo nvram boot-args=&quot;-v -x&quot;



When installing the update and booting in verbose mode I keep seeing the following line around 30 times:
Failed to send exception EXC_COPRPSE_NOTIFY. error code: 5 for pid 94
...
X68PlatformPlugin result 0

Etrecheck Report
Interestingly the Etrecheck report tells me that the update was installed:

Software Installs (past 30 days):
Install Date Name (Version)  
....
2020-07-06 Sicherheitsupdate 2020-003 (10.14.6)


But the Update keeps showing up:
I did figure out the culprit was a piece of software that was loaded using LaunchDaemons that somehow prevented a clean shutdown or startup. After backing up and deleting the LaunchDaemon files the update could be installed without any problems.
I could find more infos on the website: https://helpcenter.graphisoft.com/knowledgebase/75010/