CPU fan maxed for 10min after startup

I have a B450 tomahawk max and cooler master hyper 212 and every time I boot my pc cpu fan gets maxed for exactly 10 minutes. Temps are around 40c and my bios fan curve is set to: 40% @ 0c 50% @ 60c 75% @ 70c 100% @ 80c

Any ideas what could be the cause for this? The fan stays quiet after this but for 10mins every day it sounds like a jet engine.