Running with Oracle as the metadata backend is totally un-supported, so you are largely on your own here, sorry. I can give you a few pointers though.
Changing the timezone behaviour could have this, if the value is written as one TZ (UTC) but coming back as another (local). A better option if it’s available would be “timestamp withOUT timezone”. That way the code in Airflow to ensure that the TZ is always written as UTC (see https://github.com/apache/airflow/blob/v1-10-stable/airflow/utils/sqlalchemy.py) will not get confused and convert form local to UTC when read back out.