i would recommend going to the hobbywing thread, but as far as i remember, this was always a problem with the software being to narrow in the sensortiming. and with some motors the esc looses the rotor position then and switches into sensorless mode. i think in the hobbywing thread cobra posted a updated 211 software with is less narrow on the sensors so it should work with really any motor.
Yokomo BD7 -- Hobbywing v3 -- Sanwa M11x
May the grip be with you ... always!