T480s will not boot from NVMe M.2 drive via Thunderbolt 3

As the title states, I cannot get my T480s to boot via Thunderbolt 3. I have 2 NVMe drives (1x Linux, 1x Windows) and they both boot fine when connected via the mobo.

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I've read through several related posts online and tried several combinations of BIOS settings but still not look. Current settings are as follows:

- Thunderbolt BIOS Assist Mode: Enabled

- Security Level: No Security

- Support in Pre Boot Environment, Thunderbolt device: Enabled

- Secure Boot: Disabled

- Intel SGX Control: Enabled

- UEFI/Legacy Boot: UEFI Only

- CSM Support: No

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Also wondering if the USB-C to M.2 enclosure could be the issue?