In Wikipedia (yes, yes, it's not really a reliable source of info) :
"Detailed reports from the Bali to Jakarta incident, the flight prior to Flight 610, in which the aircraft was involved, revealed that the aircraft had suffered a serious incident. Passengers in the cabin reported heavy shaking and a smell of burnt rubber inside the cabin. At some point, the aircraft had dropped for more than 200 ft in a few seconds. Many of the passengers were left traumatized by the incident.[112] The seat belt sign was never turned off from take off to landing. The ATC recording indicated that the pilot had called for "pan-pan", which experts call as the second highest alert level after Mayday call. However, the crew of the flight decided to continue the flight to Jakarta.[113] A photo of the aircraft's logbook revealed that during that flight, the aircraft suffered an unspecified navigation failure on the pilot's side, while the co-pilot's side was reported to be in good condition.........
...............Further examination on the aircraft's instruments revealed that the aircraft's airspeed indicator had malfunctioned for its last four flights.......................
...............Report stated that, based on the preliminary findings, the aircraft could abruptly dive by mistake. If there's a malfunction in the aircraft's AOA sensors, the aircraft's computer, which is designed to prevent an aerodynamic stall, may think that the aircraft is stalling. Thus, it may cause an abrupt dive. The Federal Aviation Administration urged every airline which uses the Boeing 737 MAX 8 to heed the warnings.
.........................On 7 November, the NTSC confirmed that there had been problems with Flight 610's angle of attack (AOA) sensors.
................... Initially, the aircraft suffered an airspeed indicator problem for its last four flights. The penultimate flight was the Bali to Jakarta flight. Thinking that it would fix the problem, the engineers in Bali then replaced the aircraft AOA sensors, but the problem persisted. A 20 degree difference between the AOA left sensor and right sensor was recorded. The NTSC confirmed that Flight 610 suffered the same problem with the Bali to Jakarta flight. Just minutes after takeoff, the aircraft abruptly dived. The crew of that flight, however, had managed to control the aircraft and decided to fly at a lower than normal altitude."
What the heck -
if this is to be believed, this plane is in a totally unflyable state, let along used for service duty. They probably needed to run a test flight and check again before letting it go back to service duty. The fact that the plane had problems right from the beginning and was not fixed for many flights, they really needed to take it out of commission for further testing before putting it back into service after it's been tested and proven that it would be air worthy before putting it back into a commercial flying pilot's hands - who may not even be aware of the problems with the planes... and like Jwocky said.. who may be too dependable on ap, unfamiliar with its characteristics, may have been unable to deal with what all the previous pilots were able to deal with previously.