all_tables - what does user SYSTEM see in PDB/CDB under 12c?

I'm a bit puzzled at the moment. I have a PDB and a PDB01  in a multitenant CDB instance. PDB contains a schema owned by CHRIS.

PDB01 contains a schema owned by CHRIS01 plus another schema owned by CHRIS.

When I log into PDB01 as USER CHRIS01 and do a SELECT OWNER, table_name from all_tables where table_name='ENV' ; I'm getting

OWNER     table_name

---------------------------------

CHRIS01    ENV

But logging into SQLPLus  as SYSTEM/password@PDB01 I'm getting:

OWNER     table_name

---------------------------------

CHRIS01    ENV

CHRIS        ENV

Why is this?

--

Christoph