I have exaclty the same issue on my '16 triple since I changed stock pads.
I have read simiilar thread at rat forum and my opinion is the same and I think crashmasterd is right
It's caliper problem, especially seals one. People bled system many times, replaced, pads, master cylinders, even ABS unit - problem returns in a while - it's piston and/or seals dirt/damage.
Also, when fitting calipers, always pump brake lever and hold it before tightening caliper mounting bolts, as manual says.