JJ. My MES30 has done this a few times and Todd said it right, "farts out the side", I had my loader turned to the unlock position before and it shot it out onto the deck when it passed gas, the smoker was just not breathing right. As stated above do not overload the chip tray, since I lowered the amount of wood used I have not had the same problem. As all smokers these things have a learning curve but once you get it figured out they are great. Not sure why your temps are that far off, when I get my setpoint above the 200 deg mark it will run within 5 deg of my ET732, below that can be a good 30 deg off.
For now I would lower the setpoint, open the door to let out the heat and humidity then just monitor and take good notes for the next trip.
Sounds like you are breaking it in right, full load of goodies, good luck my friend.
Gary