Hi Steve,
Thank you so much for spending so much of time on this minor issue that is really tricky.
Yes, I had already tried
"Scale to Fit Paper" option as well as the "High Quality" option .
The printer driver has already been updated to the latest version since months ago, as an effort to ensure the printer compatibility with Windows 10.
Unfortunately, the print out still has the 'shrunk' background.
Yes there are quite a number of people affected by this issue, as the powerpoint template is our company's default template to use.
The flatten PNG solution works - but I don't know how many PowerPoint files I would need to change/flatten for all the users.
Anyway, I had attempted to print the file on a stable release (16.0.7070.2033), (to be exact, I had uninstall my First Release, installed with Stable release, and printed a copy) it printed as it was displayed. (i.e. no shrinking issue)
I guess this is beyond something we can troubleshoot around (since this is really tricky and happened only on FujiXerox + recent Office 365 First release)
Worst come to worst, I might just reinstall Office 365 stable release on affected users' PC.
Again, thanks very much Steve, let's hope Microsoft product team will pick this up and fix it. :)
Cheers.