Odd Drinking Behavior from Blood

I am the owner of a 1 1/2 year old male matrix blood, whom I have had since the summer. Everything has been going rather well with him, aside from the occasional food refusal, but he has jumped back to eating after I’ve let him skip a few feedings. He does have this weird behavior though that slightly concerns me, that he has done since I first got him. When he drinks water from his water dish he sticks half of his head under and drinks till he starts blowing bubbles in the water, then comes up for air. He does it a few times then he is done. I have noticed him go to drink water maybe a third of the time after I take him out. I figure he drinks right after I take him out because the humidity in my house is lower than the required humidity for bloods (I keep the enclosure at about 60%) and he generally prefers to stay in the same hiding spot, not moving around the enclosure a whole lot. I haven’t seen his odd drinking effect his health, but it does make me uneasy when I hear him blowing into it. I worry that the bubble blowing is a sign he’s breathing it in and that it could trigger an RI. Anyone else ever see this before? Any measures I should take to prevent him from drinking like this if it’s bad? Would digging the dish deeper into the substrate help? Thank you in advance for any replies.