Skype For Business in Line upgrade failing.

I recently encountered an odd "feature" while doing an in place upgrade from Lync 2013 to Skype4B.
This is usually next next.

After upgrading the front end pool from Lync 2013 to Skype4B i started the setup of the front end servers.
Halfway on the first server i encountered this error message:

Failed“. with error: (Error encountered: Unrecognized command line parameter "my user\appdata\local\temp...

When trying to display the log file nothing showed.
There was no files in that folder either.
So the upgrade would not continue.
The only option I found was to do this manually with deployment wizard.

I installed these msi's manually:

Sqlsysclrtypes.msi

Sharedmanagementobjects.msi

Admintools.msi

Then when starting the deployment wizard I got this message.

I chose Continue and had to deploy the standard way step by step.
I did this on all servers and the applied the latest CU.
When starting the pool I was able to confirm that everything started as expected.

Cause:
But when analyzing what caused the error, I was a bit surprised.
Seems like the in place upgrade tool is running is stores data in the \<user>\appdata\local\temp path
My admin user was with a whitespace "admin myuser".
But when looking at the error above i only saw the last part "myuser".
So when reading form the appdata path something got ugly.
Seems like the in place upgrade wizard cannot deal with a "space" in the username.
Bad coding?
And for the record. A username with a space was not of my choosing :)

Update: Have confirmed this at another installation.
Conclusion: Until Microsoft fix this glitch, never start upgrade logged in as a user with space in the username.
(Or do it manually the way i did above)