Hi,
We face the same issue whenever there is a network event. We are running version 11.0.2-h2 on models PA-3420, 3410, and 1410. If an internet circuit blips, and causes a routing change, or even when we do software upgrades on the access switches, this will cause DHCP relay failures. We host our DHCP servers in AWS. We have been deleting all the DHCP relay server entries, then adding them back, in order to resolve the issue. I think next time this occurs, we will try restarting the routing daemon via cli commands, at least until we figure out this bug.
These routing events show up in the system log, after the DHCP relay settings are changed.