I'm running MAC El Capitan v10.11.3 and Pulse Client v5.1r7.0 and periodically I experience VPN session disconnects. Sometimes my session stay up for hours other times I 'm repeatedly disconnect every 30 seconds. Its all very random. Rebooting only helps for a short time. I've confirmed my local WiFi is solid and that the local firewall is turned off.
This problem would be difficult to diagnose without looking at diagnostic log bundles. Is there a way you could work with the system administrator who manages your Pulse Connect Secure gateway to create a ticket with Pulse Secure and send a log-file bundle to us?