Edge caseWhen the puck leaves and comes right back
If the puck exits the attacking zone and an attacker is still inside, that team usually has to clear before playing the puck back in. Fans often think the first dump-out resets everything instantly, but delayed offside logic means the players still have cleanup work to do.
Common argument"His skate was in the air, so he was offside"
Not automatically. In many codes the question is whether the skate was still above or breaking the plane of the blue line, not whether it was physically touching the ice. That is why replay often zooms in on skate position relative to the line rather than looking for blade contact with the surface.