I think I know where there is some confusion...
This is the order the maps are actually in, when you go through the doors
River of Flames F1 - Safe zone - No player drops
River of Flames F2 - Safe zone - No player drops
River of Flames F3 - Safe zone - No player drops
Lava Temple F1 - Free zone - No player drops
Lava Temple F3 - Free zone - Player drops enabled
Lava Temple F4a/F4b - Free zone - Player drops enabled
Lava Temple F2 - Free zone - No player drops
Lava Temple Maze 1/2 - Free zone - Player drops enabled
Lava Temple F5 - Free zone - Player drops enabled
Dragonclaw Caverns - Free zone - Player drops enabled
Scorching Caverns - Free zone - Player drops enabled
I've highlighted in colour the floor it sounds to me like you were on, which is technically the fifth floor that you get to, so I can understand why you'd think that is the fifth floor. But, notice River of Flames F1,F2,F3 and Lava Temple F1,F2 are all no player drops, which is what I take to mean from the website.
It is rather confusing that these are in the wrong order, I think it's just the doors have been placed wrong, but it's certainly always been that way in my experience. I did have a message from someone a couple of days ago who was trying to reach the maze and found himself on "Lava Temple F2" and thought he'd gone back on himself, gave up and went back to town!