Hello
Bitlocker encryption is enabled out of box when you set up the computer. The key is stored in your Microsoft account.
https://account.microsoft.com/devices/recoverykey
If update involves BIOS update or TPM driver update, it can trigger the ask of bitlocker key.
You do have to enter the key in order to get past this to get back into the computer. Then search for "bitlocker" in the search on taskbar to launch the settings page, turn it off so it will never happen again.