Wrong info in Username and Full Name fields

Hello all,

I'm seeing an odd thing in our inventory in JSS (v9.9.2) where some Macs will show root as the current User and a completely random name in the Full Name field. The name will show up for all the Macs that are showing with the User root. I can't seem to make heads or tails of why some Macs start reporting this. Today there are 22 Macs showing up this way (image attached).

We do have a Last User extension attribute enabled:

#!/bin/sh
lastUser=`defaults read /Library/Preferences/com.apple.loginwindow lastUserName`

if [ $lastUser == "" ]; then
    echo "<result>No logins</result>"
else
    echo "<result>$lastUser</result>"
fi

As well (and I suspect this is where it's going a bit wrong), we are auto-populating the Full Name field by pulling the current user. Here's the script from JAMF Nation we are using:

#!/bin/sh

sleep 5

loggedInUser=$( ls -la /dev/console | cut -d " " -f 4 )

/usr/local/bin/jamf recon -endUsername $loggedInUser

exit 0

I've seen some other discussions where having multiple users logged in via Fast User Switching can cause issues, but we have that disabled on most Macs.

Thanks for any suggestions!