XPS 15 9570, docks, fans spin on low temps

I have recently bought a XPS 15 9570 i7 that have a big problem of being quiet when idle. When I have it connected to either a WD15 or TB16 dock, the fans are always on with cpu temps around 40C. Tested this with only the dock connected and nothing connected to the dock and the behaviour is the same. When pulling out the Thunderbolt connector the fans stop from constantly spinning after a few seconds.

Without the any dock connected, the fans randomly spins up for 3 seconds and then stop even tho the computer is idle and CPU temps are ~40C.

The fan curves are probably set to start at low temps and not prioritize a quiet environment. Changing the thermal setting to Quiet in Dell Power Manager doesn't help.

I also tried bios from 1.5, 1.6, 1.7, 1.8.1 but the fans still run constantly with a dock connected and temporary spin up when computer is idle.

My guess it's some other chip that the CPU that trigger the fans, maybe the PCH. Apparently this chip is not even cooled by the fans so why even start them if it gets hot?

Why Dell haven't solved this problem is beyond me. This is a newly designed laptop and the problem what ive read have been plaguing similar Dell laptops for years. 

Some posts about this and other similar laptops from Dell.

https://www.reddit.com/r/Dell/comments/8rjtq8/fans_go_onoff_all_the_time_on_dell_xps_15_9570_i7/
https://www.quora.com/Why-does-connecting-a-USB-C-hub-causes-my-XPS-laptop-fans-to-spin-with-no-load
https://www.dell.com/community/Laptops-General-Read-Only/Dell-XPS-15-9550-Thunderbolt-and-Fan-Speed/td-p/4761018
https://www.reddit.com/r/Dell/comments/82ntdd/annoying_fan_noise_upon_connecting_the_tb16_dock/
https://www.reddit.com/r/Dell/comments/5s6mc3/xps_9560_fan_on_idle_while_charging_plugged_in/

The fan curve on the XPS 9570 needs fixing, many of the solutions Suggested too generic. Putting it on quiet doesn't work, disabling turbo boost doesn't work. A quick way to test the issue is to press F12 on boot up, go to Dell Diagnostics – "ePSA Pre-boot System Assessment). From there look at the System health and you will see that temps never get past 49C, and the fans keep cycling from 0 – 2504 RPM. It does this every 20 secs or so. This eliminates any concerns about windows running something it shouldn't. Dell engineers I urge you to go to a library with a Dell XPS 9570 laptop, plug it into the AC wall charger and just use it in a very quiet environment and be surprised at how often the fans kick in when you are doing absolutely nothing extraordinary