I have installed 7.1.0.2 and facing the same issue. I was able to delete 1 of 4 masterserver even it has shown as deleted. After restart (take notice that the restart is taking very long as i think it is just recovering what has been deleted before). I didn't open a case as it was on my test system but the behaviour is the same on 7.1.0.2.
As far as i can remember is one different step that i have made is a backup after deleting the master. This master did not appear also after a restart.
If you open a case i would be interested on the solution.
Ramazan