create pluggable database ORA-28374: typed master key not found in wallet

I'm attempting to move a pluggable db between containers.

I already created five PBS in the same container specifying the same password but now the pdb is refusing to create with the above error.

create pluggable database <NAME> using '/home/oracle/XML_FILES/<NAME>.xml' keystore identified by "<PASSWORD>";

As I said the same password worked for 5 previous PDBs unplugged from the same source container and added to the same target container db.

I was also able to plug the PDB back into the original container using the same password.

I don't follow why the master key is suddenly wrong for this PDB. If the password relates to the container db's TDE wallet, why did it work for the previous 5 pdbs. If it relates to the PDB itself why did it work to plug it back into the original container? And mostly why won't it work now?