I’m pretty sure “anchoring” is putting your pinky on the body somewhere below the strings and that definitely is troublesome when you want to play hybrid picking, the thing you’re talking about is a typicall muting technique which i don’t consider a bad habit, but I might be wrong. Generally speaking, if you’re comfortable with your technique and it doesn’t hurt you or stand on your way to playing the way you want to be heard and to hear yourself, it’s probably ok.
What’s interesting, though, is which part of your right hand you use for muting. I mute high strings with the outer flesh of my palm, the below your pinky, and for the low strings I use my free left hand fingers. I would never have come up with the idea of muting my low strings with any part of my right hand, and especially with the one just below the thumb.