Ok same experience here but solved with redline likewater suspension fluid. Think its lighter than 2.5 too.
Wouldn't worry about warranty, just pump with shimano stuff if you need to send it back

I'm currently running xtr 12sp rear mech with sram cassette and x01 shifter. Got rid of the sram because the type 3 clutch is garbage and not adjustable. Absolute game changer. For some reason I had to constantly fine tune the xx1 and it always skipped on the 4th cog. B tension set at sag.
The shifting is more precise, and setup was easier with the 51t mark on the derailleur cage. Running with kmc chain too.

I've got 2 conflicting views here. Had a really bad experience last year racing the MT7s on the megavalanche. Virtually no braking from halfway down, completely cooked them. I only found out later the magura mineral oil has a boiling point of 120 degC! The levers are also terrible and I had them all including the hc3s. You actually lose some mechanical advantage with the hc3s too.
With the shimanos the problem is with the viscosity of the mineral oil and the small master cylinder port. The oil simply can not return fast enough hence the variable bite point. Use something very low viscosity like redline likewater suspension fluid and the problem disappears. Plus a higher boiling point.
I'm about 110kg and race alpine events, I have tried everything out there including new cura4 and trickstuff.

Nar, yeti Asr7 with wagon wheels. Not a bad thing tho, they were monster trucks

Same experience here to the point where the pinch lugs have bent slightly