I would check the following:
- Check the column type
Check whether the field is a calculated or formula column. Its value may be changing automatically based on other data. - Check business rules
A business rule may be setting or changing the field value. - Check plug-ins
A plug-in may be running when the record is created or updated and changing the data. - Check classic workflows or other Dataverse processes
An existing process may be updating the record automatically. - Check Power Automate flows
Check whether a flow triggered by the Dataverse record is updating the field. - Check the record’s audit history
If auditing is enabled, review the audit history to see when the field changed and what caused the change.


