same set up,same problem but i also use a Spektrum cap but it doesn't make any difference. Sent the ESC to repair ,i'll see what happen when it'll get's back.
I'm thinking about selling it right away,castle made it again like it did with the first batch of MMM .
Besides,i've turned on a brand new MMMv3 yesterday,it made the first beep,it turned on just the yellow led and then it's gone,dead. . . . without any smoke coming out of it . . .both replaced today with a coupple of Tekin's (RX8/RSpro) both working fine.
I wont get Castle stuff anymore.