So this was a weird one, and it doesn't seem like some of the symptoms were what I thought they were.

It appears that Microsoft broke some things in their latest Windows 10 update (hooray for automatic updates, amirite?!?!) that caused a bug when connecting to some L2TP connections. If you click the network icon in the system tray and click on your VPN, it just spins and spins and never connects. If you open your settings, go to network, then VPN, then click on your VPN and click connect, THAT will work. Extremely annoying. Clearly a bug that Microsoft introduced. It appears to only happen on the 1903 release.

It looks like the users who were able to connect but having weird problems are no longer having those problems. They seem to have cleared up on their own for some unknown reason. My least favorite IT problem is always the one that happens occasionally. I prefer when it works or it doesn't

Anyway, thanks for the input, Tony. Sorry to waste everyone's time. Please blame Microsoft :p