I detected what it looks like a serious safety issue: in a specific situation, power brake completely turns off, without any alert.
It happens when parking.
Test this:
1) park down hill
2) put in R and move backward 1 meter or more
3) put in N and go down hill for a while
4) put in B while moving
5) now brake ... if you can! But you can count only on your force, as power braking is completely disabled!