Trying to track down a repeating ORA-00900

We run Oracle RDBMS 19.25, non CDB, on Windows 2022 server. Oracle 19 was installed on new server and existing Ora12 db was imported.
This db serves a locally developed Web app running mostly 'C+' code and some older asp and aspx pages.

I have 2 questions.

1.How can I locate the sql that is that generating this Ora-00900 error. The sqlid is not present in the v$sqltext.

WARNING: too many parse errors, count=101 SQL hash=0x74d7d5a8
SQL: DBMS_SESSION.SET_IDENTIFIER('Domain\UserName)
PARSE ERROR: ospid=17996, error=900:
Additional information: hd=00007FF853997F68 phd=00007FF8E1DE12B0 flg=0x28 cisid=106 sid=106 ciuid=106 uid=106 sqlid=byb9n7xudgpd8