I can smell gas near the exhaust at the top of the gas water heater (Dux 135L) right after the flame goes out. Its not very noticeable, i only discovered it when a friend came over. But i can definitely smell it now. The pilot light stays on and everything works fine. Is this normal? I found a post here talking about the gas smell as if it's normal for all gas appliances. Someone in that post talked about pilot light too, does it mean it will burn the residual gas if the concentration starts to build up? I can't really smell anything when it's on.
Edit: found the post I was referring to
https://www.ozbargain.com.au/node/459525
You have a gas leak.
Evacuate now, call gas plumber asap.