Mushy brakes 4 life...

I have never bench bled a MC in my life. Race car or street car. It never made sense to “ ok it’s perfectly bled, now empty it and put in the car and hook it up”. I’m beginning to question either wheel cylinders or that master. New Junk is common now.

Perhaps unbolt it from the car, throw it in the vise and bleed it. You might find your problem. You tube and internet is loaded with the procedure. Good luck.