Brushless Lst2 Problems

Have a few problems with my brushless set-up. I have an MGM 120 controller, fiegao 8xl, ubec, 4s 8000mah lipo pack.
Problem #1 If throttle epa is at 100% when I nail it off the line it will cut out until I let off throttle

Problem #2 After running for a few minutes the mgm will have a dim light on all the time and will do nothing, after 30 minutes of being diconnected it will come back to life.

any suggestions?????
Thanks