Dual-mode controllers often fall back to square when a hall sensor signal is no longer received or is unreadable.
Same thing causes the jerking and not being able to start spinning on it's own.
Since it is happening only after using it for however long, the motor could be overheating and causing the hall sensors to not work correctly.
If it works in reverse normally, then if the sensors aren't damaged, that probably means that you have a false positive hall sensor combo that is good in reverse but not in forward once the signals start to have problems, meaning that self-learning isn't working correctly for whatever reason, and you'll need to manually go thru the combinations. There are charts that you can follow, or text descriptions if you prefer, in various motor and controller and hall sensor troubleshooting threads.
If the sensors *are* damaged then working in reverse ok probably means the controller is better capable at reverse in sensorless than it is at forward. Or, the reverse function is engaged, and it's terrible at reverse.
It could also just be a connection fault between controller and motor, anywhere between the controller PCB inside it and the motor halls inside that.