This was my experience as well last month arriving from YYZ. I made it from the gate in L to F in truly 5 minutes. About half an hour later it hit me that I hadn’t gone through security. I’m not 100% sure but I think this is only possible with the L gates on the west side that can unload passengers into a separate corridor that doesn’t touch the main L building, which then connects to the L-F passageway.