Yes, there is a menu entry calling UI_ACTION_TOGGLE_JAMCONTROL to switch it on/off.
One solution to find reason is to modify
void TemperatureController::setJammed(bool on) {
if(on) {
flags |= TEMPERATURE_CONTROLLER_FLAG_JAM;
Printer::setInterruptEvent(PRINTER_INTERRUPT_EVENT_JAM_DETECTED, true);
} else flags &= TEMPERATURE_CONTROLLER_FLAG_JAM;
}to not set the flag which triggers the jam, but instead report jamStepsSinceLastSignal so you see on which value it got triggered, but do nothing else so print is not ruined. Then you know what your critical value is.