Steps to reproduce:

1. Assign the "Oracle by Zabbix Agent 2" to a server running (in this case) Oracle Database 19c Enterprise Edition
2. run the PDB Discovery

Result:
**

Cannot create item: item with the same key "oracle.pdb.info"{$ORACLE.CONNSTRING}","{$ORACLE.USER}","{$ORACLE.PASSWORD}","{$ORACLE.SERVICE}","{#CON_ID}"" already exists.
Cannot create item: item with the same key "oracle.pdb_open_mode"{#CON_ID}"" already exists.

Expected:

No error and items created

Extra info:

The discovery rule returns this data:

[{"{#DBNAME}":"PDB$SEED"},{"{#DBNAME}":"**********"}] 

There is no {#CON_ID} in the result set.  Replacing {#CON_ID} by {#DBNAME} in both Item Prototypes solves the issue in this case, but not sure if this is a valid solution for multiple CDB/PDB's