The second behaviour you describe may be due to a faulty door detection. See this thread for a description of the problem in detail. Long story short: SM2 assumes that the door is closed, until if was opened once. If it does not register the door closing again, e.g. due to misaligned magnets, it will keep the laser at safe power levels, assuming the door is still open. You can check door state with GCode M1010. Solution: Realign door magnets with sensor.