MJ23 listen to this personMaybe you're pulling the air through the filter to fast. If it's going through too fast the odor won't have enough residence time going through the carbon to react. Put a speed controller on the fan, slow it down a bit and that should take care of the problem. I have to do this with my set up. Otherwise the odor will pass right on through.
I know, I know. You say, but my filter is rated for xxx cfm and that's what my fan pulls through it. Mines rated for over 1100 cfm and my fan pulls 1019cfm. It'll pull odor through it every time if I run it at full speed. Slowed down it works. Try it out and see what happens.
Now, as others have noticed and mentioned, you're not exhausting out of the room.
You're pulling so much air through the fan/filter that you're pressurizing the room. Over pressure so to speak. What ever smell that is there is being pushed out the room by whatever means it can find. This push out of air is also adding to what you are now smelling. Air is like water. If there's a way out it'll find it. Around the door, the frame, the window, window frame, etc.
Hope that made a little bit of sense. I'm a bit stoned blurry at the moment.