ORA-25412 sporadic error after migrating to Enterprise with Dataguard

After migrating from Oracle database standard 19.patch15 to Enterprise 19.patch20 (two servers with Dataguard), the existing application is receiving errors ORA-25412 after some time of correct behaviour. For example:

"OraOLEDB / claDB - Select_ ORA-25412: transaction replay disabled by call to OCIStmtPrepare","Connection : 0 - SQL=<SELECT E2S_SYSDATE FROM DUAL>"

The tnsnames.ora on the client is only configured for one server IP, and SERVER=DEDICATED.

Since the client application (Siemens brand) uses the OLEDB driver, I think the OCIStmtPrepare function is called inside the ODAC193 dlls.

Is this problem already known by someone?

Thanks,

Alejandro