10g - ora-01097 during shutdown immediate

strange thing happened today in testing 10.1.0.4 <http://10.1.0.4> patch 5 Std Ed on ms w2k adv svr.
(this patch included a bug fix that we needed)

started up a new session with sqlplus.
connected as sysdba.
selected against v$database, v$instance. disabled restricted session
tested login with an unprivileged account - ok. made a parameter change in the init.ora. going to cycle it for the change to take effect.

SQL> shutdown immediate
ORA-01097: cannot shutdown while in a transaction - comit or rollback first

SQL> commit;

Commit complete.

SQL> shutdown immediate
Database closed.
...

no database links in use, no distributed transactions. how could I have a transaction open in this session with no DML applied, or selects across db_links?
there were no other sessions in the database, except for background jobs.

I did check out Note:310956.1 but that did not seem to apply.

cold backups are not in use there, but it sure seems like if I were using a scripted cold backup routine, that I'd want to throw in a commit/rollback prior to the shutdown immediate.

Has anyone else seen anything similar?

I'm thinking that a likely recipient of blame would be a logon trigger that did not commit, but after logging onto a new session, there are no active transactions in the system ... and now I am not permitted to shut this down until after close of business to test further.

Paul

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