I bought, installed, bled and bedded in a set of Trail Sports with brand new MDR-C rotors and sold them after 5 rides because of the gurgling sound. I have experienced turkey warbles, but never gurgling. I went back to 2 piston 8100XTs front and rear with Shimano resin pads and literally could not be happier.
As for the Shimano Wandering Bite Point? As soon as I stopped doing the internet's highly recommended 5 minute lever flick/bleed with the wheels and pads installed (which overfills the system) and went back to following Shimano's bleed procedure to the letter (pads out/yellow blocks in), the WBP vanished like a fart in the wind.... Dead nutz consistent.