My guess would be that when you had the lid open and moved the coals about, then put the lid back on, thus causing the temperature to drop and the fan to kick in hugely (it's on constantly for the best part of 20 minutes and at high percentages too), this extra heat caused the coals to burn a lot hotter and increased the amount of area on them that's burning which will of course give a higher temperature which will take a good while to come back down.
This is the same problem I had when I first used my qmaster and let the fan bring the smoker up to temperature, or indeed if I'm not careful about unplugging the fan when I remove the lid and only plug it back in once I've given the smoker a chance to get back up to temperature which is generally does as the coals where in the right condition for the temperature I wanted before I lifted the lid.