Smell in house after cellulose insulation blown into attic

About 1 month ago I had cellulose insulation blown into my attic. In one part of the attic it was dense-packed.
Immediately after the job was done we began noticing what frankly smelled like a diaper pail type smell on the second floor, particularly noticeable in my 3 year old son's bedroom which was right below where the dense-pack was done. The smell has not gotten noticeably any better with the passage of time.
Interestingly enough, I don't actually notice the smell in the attic, but it was definitely not a smell that was present prior to the insulation job being done.
We had the installation company and an independent inspector come back out to us to talk through the problem; the inspector said his best guess was maybe that problem wasn't necessarily the insulation creating the smell but perhaps preventing something causing the smell on the second floor from dissipating in the now more airtight parts of the home. I can't fully refute that but it seems like a stretch that all of a sudden we'd notice that smell immediately following the insulation work.
Does anyone have any thoughts / experiences to share on this issue? Thanks!