It looks like you are pre-provisioning bitlocker during your task sequence but the "Enable Bitlocker" step is not running at all. This step, which typically would be towards the end of your TS, sets up the "protectors" and actually enables bitlocker.
You can try running the following commands to see if you can get bitlocker enabled on a unit. If it works, check the step in your TS that enables bitlocker.
manage-bde -protectors -add c: -tpm -rp
manage-bde -on c:
I hope this helps.