The beginning of your screenshot looks like combustion to me. When my wood has caught fire in the #2, it usually happens on the first heating cycle in the 180-190* temp range. Did you see some heavy puffs of smoke coming from the top hole at this time, and a loud exhaust sound (we call it the burp)? It looks like this might have happened a couple of times given the way the temp goes up and down and back up again around 7:45-7:50 on your graph.
When you set the temp to 225, the #2 will cycle above and below that setting throughout the heating cycles (+/- 25* or so). I have noticed that the variance in the temp swings diminishes with time during the smoke.
I would continue monitoring the temp with your app and keep the smoker setting at your desired temp. If it continues heating up without the element shutting off, then it is possible that the temp gauge in the smoker may not be registering the smoker temp correctly.
Hope this helps.