i believe its setup related as well....i had a MM as well but did the fan mod and added a cap...it began to do the same exact thing that your did except when i was going low speed throttle it stuttered then then "POP!" smoke came out from under the body...luckily that "POP!" was a blown $10 capacitor
..... this whole problem , as i eventually found out" was related to my gearing....it was in an overgeared e-revo on 5s.....so i changed the gearing, added another cap, and my MM has outlasted my revo and now is a back up to my fully functioning MMMv1 and MMMv2....i;ve also owned 5 cc bec for about a year and they have all worked flawlessly...guess you got a bad batch or something
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