BUG on GRE interface page
After I put the tunnel up again manually without LINK2, it worked.
Don't matter if you enable or not the WCCP version checkbox, ifconfig always shows LINK2.
Thanks for the report, I can confirm it is a problem and I opened a ticket for it here https://redmine.pfsense.org/issues/6010 – I also pushed a fix to 2.3 for it, so it won't be a problem in the future.
They are OK at boot time, so once you have the interface saved it's OK from then on if you have to reboot.
GIF interfaces also had the same problem for interface flags so I applied the same fix there.