Failover LAG to firewall

Hi all,

Hoping somebody can point me in the right direction, I really only know a little networking normally enough to get by but I am having an issue with setting up a connection between a switch stack to 2x sophos xg 310s

We have 2 310s running in an active passive setup. To connect these to my user stack (dell n3000) I have created 2 LAGS in active mode.

Port TE 1 from switch 1 and 2 in the stack are in port channel10 and connect to 2 10gb ports on the primary sophos device. Port 2 on switch 1 and 2 are port channel11 and plug into the failover sophos device.

Lacp lags are also configured on the sophos devices.

I thought this setup should work but when everything is plugged in there seems to be packet drops all over the show.

Although the sophos devices are in a failover setup, the way they run the ports on the failover device never shutdown.

Thanks in advance for any tips to point me in the correct direction.