Losing DHCP Gateway

This problem started with 17.5.0 GA.  The firewall is handling DHCP for my lan.  Users have started to lose the default gateway(the Firewall) randomly throughout the day.  I have to either reset the switch or the desktop network adapter in order to regain internet connectivity.  This does NOT happen to all users at the same time.

I updated to XG 115 SFOS 17.5.5 MR5 but the problem still exists.  This actually introduced another problem of not being able to access the gui from Sophos Central, but that's not as pressing.  Any thoughts on this would be appreciated.

Thanks

Larnel