Resmed humidifier H4i makes noises that match my inhalation?

I've had my humidifier (H4i) for a few years but since last week, it has been making loud noise every time I inhale. I am pretty sure the noise is not from my mask, because it grows louder as I move closer to the humidifier. I've checked the hose connection, the joint between the humidifier and CPAP, and the cover itself, but all of them don't seem to have any leaks. Any suggestions? Thanks!

I had that problem with mine, what I found was that I would have to open the humidifier up and push the resivour back against the seal