I agree a 9% jump all at once is high. But mine didn't fluctuate like that, just overall from setting to lock down had a 9% difference. Once the humidity regulated it was usually around 30/32 but there were a couple spikes at 35 due to 97/100% humidity outside and rain. Didn't last long, as soon as I caught it I kicked the heat on in the house to circulate the air and it came back down.
Got cha