It's always a good idea to open an SR when you are able. I assume you already got a response from Support. For others wondering about this, the issue is most likely related to running the report against a RAC environment as noted in the following bug:
Bug 18132564 - LAST AWR REPORT FAILS WITH ORA-01422 IN RAC ENVIRONMENTS
The call to the AWR report requires parameters for both a DB and an Instance ID, so the report should either run, as in prior releases, for only the current instance, or be changed to run for all instances in the cluster.
SQL Developer Team
P.S.: And, in fact, a prior forum discussion - 4.0 EA2 - AWR and ASH giving ora-01427
lead to the following bug getting logged and supposedly fixed for SQL Developer 4.0 ...
Bug 17481944 - PERFORMANCE AWR/ASH/ADDM PANELS NEED TO SUPPORT RAC ENVIRONMENTS
... with the developer commenting
I've added a instance number selection control to the various reports: ASH,
AWR, Difference and SQL. The control is supposed to only be visible when the
connection is to a RAC system, so testing will need a RAC.
So if you are not on a RAC system, or are on RAC but do see the instance number selection control, please let us know.
Message was edited by: Gary Graham
Just got my answe back from support...
Bug 18132564 : LAST AWR REPORT FAILS WITH ORA-01422 IN RAC ENVIRONMENTS LAST AWR REPORT FAILS WITH ORA-01422 IN RAC ENVIRONMENTS
Fails in RAC environment ( exadata)
Works fine otherwise...
So ...using the very convenient user defined report feature...we implemented our own awr report..and we're fine until Oracle fixes it