Absolutely. In fact, in addition to simply not getting a seal, there are tons of factors that can alter the sound of something as specifically-tailor-made as a CIEM. I've experienced CIEMs with bores that were cut at the wrong angle, CIEMs that were trimmed a bit too small and caused them to fit too deep in the ear, a tighter fit causing a tense eardrum when listening, etc. What you're describing - at first glance - sounds like a poor fit. It's a sound I've sometimes experienced when the CIEMs haven't been inserted far enough in the ear. So, you hear bass, but it's very unfocused, hazy and cloudy. Try forcing the CIEMs in as far as possible, twisting as you go to try different insertion angles. If nothing changes or you hear a better sound but at the cost of comfort, I'd advise contacting EE for a refit.