“Phlegmy” Sound with Perrin Cold Air Intake

I got the Perrin Cold Air Intake for my 22 Base and recently installed it. So far I’m liking it. The sounds coming from the turbo are really cool (most of the time), but there is one thing that is bugging me. That greasy foam filter. When I opened the packaging I found the thing marinating in grease. I have never used a filter like this but followed the instructions and cleaned off as much of the grease as I could. It was a pain in the ass to install but I did exactly as the instructions said. When I’m driving around, I occasionally get this “gurgling” noise from under the hood instead of the cool turbo noises. I am really not sure why this is happening. Google says this is because of the greasy filter and is normal on an occasional basis. Is this true?