Try to disable Firewall on wife`s PC & then check for updates again. Malwarebytes could block access to update servers. try to uninstall it. Also it could be Emsisoft Anti-Malware.
That's normal because the new release is only delivered in small amounts slowly over a period of time. I guess the other machine is using a different server at the McAfee end. It will catch up eventually and at no time is your protection in doubt.
Each time the same thing: when I become impatient and ask here for a long update then I have it just after....
Update this morning and all versions numbers are the same now!
LOL, glad it's OK now.