Source:

https://www.microsoft.com/en-us/legal/intellectualproperty/t...

https://www.paragon-software.com/exfat-license/

https://en.wikipedia.org/wiki/ExFAT#Legal_status

You maybe of the hook if you use Linux >= 5.7. And it seem that you are of the hook if you are a member of the Open Invention Network (OIN).

But SEGGER's embOS is not based on Linux and their costumers a OEMs themselves. So their costumers would need to be OIN members or pay royalties to MS.