On macOS and Linux Pulse Secure will modify the /etc/hosts file when it starts the VPN session and remove the modifications when ending the VPN session. If Pulse crashes or does not exit cleanly the modifications remain in the /etc/hosts file. If that information is somehow not correct at the start of the next VPN session Pulse will not be able to make a connection.
It seams that the Pulse shoudl also remove the /etc/hosts modifications when it starts up if those modifications are still in the hosts file. This has casued a few dificult to resolve issues in our enviroment.