WAN bridge mode no DHCP update

Hello Mandeep Baidwan1,

Thank you for reaching out to the community, you may add static neighbor ship for that interface: 
> Add a static neighbor: https://docs.sophos.com/nsg/sophos-firewall/19.0/Help/en-us/webhelp/onlinehelp/AdministratorHelp/Network/Neighbors/ARPNDP/NetworkStaticNeighborAdd/index.html

Thanks for the quick response Vivek!

I may have not have phrased my question correctly. I want the WAN link to pick up the new WAN DHCP address which only works after I reset the interface - not sure setting static neighbour would help? 

Thanks for the quick response Vivek!

I may have not have phrased my question correctly. I want the WAN link to pick up the new WAN DHCP address which only works after I reset the interface - not sure setting static neighbour would help? 

Hmm interesting, so before the issue and after the issue can you share a screenshot of Neighbor configuration > show ipv4 Neighbor cache for that interface ?

Sure thing, pictures below. I can see after the router is reset the IP address isn't updated... but I'm not sure what that means :). 

Before router reset (all working)

After Router reset (no connection)

After resetting interface (all working)

This may be the issue, are facing a particular problem with this interface only or this router?
Can you try changing the interface and the router see if the issue persists?