IPv6 requires a ping or traceroute to reactivate

So I'm running into a weird issue with my UTM:

IPv6 is running on both clients, however, if I let them sit for more than 20 minutes without using the ipv6, I have to issue a ping to the UTM, then traceroute, then i can use ipv6 sites.  Is there a setting that I'm missing so I don't have to ping out every 20 minutes or every time I come back to the computer?  I'm using a native ipv6 stack, and I do have an app that is in the background (Microsoft Office connected to Office 365) that uses ipv6, so it should keep the connection alive, but it doesn't.  And it doesn't matter if it's from my Mac or my PC that i try it, it always is required something to reactivate the connection.  IPv4 works fine.

Any help would be greatly appreciated!

Thanks