IPv6 address allocation

[cmr]

At one location I have an ISP router that has IPv6 set up and is set to give LAN devices an address via DHCPv6.  Behind it is an MX75 and it receives an IPv6 WAN address automatically, but it shows that there is a problem with the message below:

I'd like to fix it, but clicking on the link simply opens a new tab on the same page.  There doesn't seem to be any documentation either...

[cmr]

The link erroneously includes the current dashboard page followed by a messed up link to the documentation, but that is for IPv4 and suggests that it is caused by a bad static IP on the WAN.  In my case the message appeared only after getting the WAN to obtain an IP via DHCPv6...  The link is:

https://nxxx.meraki.com/Network Name/n/s53BFbhd/manage/nodes/new_wired_status/https//documentation.meraki.com/General_Administration/Cross-Platform_Content/Alerts_and_Notifications/Common_Dashboard_Alerts_for_Device_Connectivity#Bad_IP_assignment_configuration