Windows 11 has a fun feature where it will potentially deactivate if you update your bios.
https://www.theverge.com/2023/11/15/23958751/microsoft-windo...
https://www.theverge.com/2023/11/15/23958751/microsoft-windo...
Then again, the manufacturer probably should've made sure the replacement motherboard was covered by a license.
If you're using a Win 10 upgrade or Win11 fresh key, it's expected you wouldn't encounter it.