does your bator have a temp probe attached to a wire? like this: can you see the "L" shaped probe? that is the heat thermometer. is yours like this? if so, i use to have temp spikes until i make sure i place the probe directly under the heater. does this make sense? try this and see if it makes a diff w/your temp spikes.
That is exactly like mine. Right now I have it near a cool spot to keep the temp a lil higher in bator. That cool spot was reading 94.5 and now that I have it there it is reading better throughout. I dunno if I tried directly below the heater though I know I've at least been close. I almost wonder if the fan is just not blowing but I don't wanna remove the lid that long to check and drop my humidity too low.