Sharing TDE encryption keys between PDBs

We're moving from non-containers to a multitenant architecture. To facilitate production to non-production cloning, a common encryption key is used. So, say DBPROD, DBDEV and DBQA. Each have their own wallet/keystore.

When I move to multitenant, the plan is a production CDB with a PDB for DBPROD. Then a non-prod CDB with 2 PDBs - DBDEV and DBQA.

If I am using TDE united mode, I have a single keystore for the non-prod CDB. I want to use the same encryption key, but it seems I cannot.

AI keeps saying I can, but the command do not work. If I have DBDEV using a specific key and run "ADMINISTER KEY MANAGEMENT USE KEY…" to assign it to DBQA, its reassigned.