LG G4 Notifications with WiFi/Airplane Mode Enabled

I recently updated my Verizon LG G4 to 12A and have been one of the users affected with notifications not showing up when I'm connected to WiFi. After reading through the forums here, it looks like several people have narrowed the problem down to IPv6 and that setting up a VPN (which forces it to use IPv4) is one possible workaround. Last night however, there was a storm, so I enabled airplane mode and turned on WiFi so I could use my phone inside the house. Once I did that, I noticed that I started receiving notifications over WiFi again. After the storm passed, I turned airplane mode off, stayed on WiFi and was still receiving notifications. Once I restart the phone though, it appears to go back to not receiving notifications until I enable airplane mode/WiFi again or turn on 4G LTE.

Can anyone explain why this is occurring or if they can replicate this behavior on their G4?

Thanks,