BrewPi - Temp Stability Issue

My first fermentation with my BrewPi controller resulted in near perfect temp control, within .1F. This second fermentation seems to be going quite differently, allowing for sways of up to .8. I know this isn't going to break the beer, I'm just trying to understand why it seems to not have as tight of control anymore. Here is a screenshot of the fermentation:



As you can see, early on in the fermentation the control was nearly perfect. Once it started raising the temp from 67F to 70F is where is seems to have lost control. During my last fermentation, the system never exhibited sways this high. I'm still using the same freezer/reptile heating lamp combo.

Are there any PID parameters that I should be adjusting?

 

How is your probe measuring? Thermowell? Ive had this happen when my probe accidentally got pulled up my thermowell when i closed my fridge door, it was still measuring the beer but also measuring air temp.

If your using a thermowell i recommend plugging the end after you put your probe down in.

To prevent this from happening for me again I took my fermenter, measured how far down my thermowell my probe had to go to be dead center in my fermenting wort when its full with 5 gallons. I then wrapped some electrical tape around my probe wire at that length and now i just shove my probe in until it gets to the tape and I know its at the right spot and i can use the tape as a sort of plug to keep it from measuring the air.

 

I"m measuring the beer temp with a thermowell. I'll check that the probe is still all the way down the thermowell. Yesterday I set the temp to be 70F and it locked right back into perfect control. It seems that when I ask the BrewPi to go above 70F, it starts losing control.