Smelly room, with filter should I be able to smell flowering buds?

Can you tell us what the filter is rated for?

What is the filter rated for? That will be the key as far as it's ability to reduce smell -- as well as overall quality. As long as you have a slight negative pressure, and the filter is proper, it shouldn't be too strong. Better off piping it outside. May find that helps reduce smell if it can't build up over time. If it leves ~5%, that room will fill up with a higher concentration that what the filter is providing. Usually those 4" filters are ~160cfm rated... going over that reduces effectiveness. Check the specs. Those adjustable 4" fans usually don't reduce more than 20-25%, unless you got a nicer one. If not, now worries, you'll be replacing that $30 fan within 1 year for sure, unless you are a lucky one.

It’s a brand new filter purchased a month ago

How old is your filter? Did it rattle when you hang it? Some of them are not packed right and the coal is loose which reduces the performance. Is the exhaust setup creating negative pressure in the tent like it is supposed to be. Unfoetunarely I cannot calculate the cfm and the 3x3 to meters on the go :)

Hello.. Hope you are well.. In my personal opinion the active charcoal set inside ur carbon filter has depleted.. Sum can b refilled but not sure on ur make or model.. Replacing it will remove any unwanted odours again.. Stay safe n gud luck on ur greens.. 👍🍀