When you install Windows, BitLocker is part of the installed package. In terms of the question, the key point is due to issues related to TPM (Trusted Platform Module). Here are some solutions you can adopt:
1. Check BitLocker requirements and ensure that your MacBook meets all the BitLocker system requirements, including any specific requirements for using BitLocker without TPM.
2. Make sure you have an upgrade to the latest Boot Camp version installed along with all necessary drivers. Sometimes, updating these components can resolve compatibility issues.
3. Consider using third-party encryption software such as FileVault, VeraCrypt, and others that don't rely on TPM, as they may offer better compatibility with your setup.
4. If the above steps don't work, you can reach out to Apple Support since you're dealing with a unique configuration involving a MacBook and Windows through Boot Camp.
You also can refer to How to Use BitLocker Without TPM?
