SOLUTION: If you are experiencing this problem (change TPM activation state using CCTK command line, CCTK returns success, but activation state is NOT actually changed) it is most likely because CCTK cannot change the TPM activation state when the TPM is in an "owned" state. You must first clear the TPM ownership, then CCTK --tpmactivation=activate will work properly.
This is not documented anywhere, so far as I know. It's obviously a bug in CCTK. CCTK should not return success when it has failed, d'oh.