Cavador have you got a save?
I've just reloaded an old save and I don't experience zero gravity whilst in the area where the Air Talisman is, but once I have jumped down the hole and landed in the water I experience zero gravity in that room, but it all goes back to normality once I enter the tunnels after the pool of water, so if your experiencing zero gravity before you have jumped down the hole and that is preventing you from jumping down the hole then that is not right.