Message appears on a Formula Field when a Record is edited: "This field is calculated upon save"

Why This Message Appears

Starting in Salesforce Spring '20, the message "This field is calculated upon save" appears on Formula Fields when a record is in edit mode in Lightning Experience. This is expected behavior, not an error or malfunction.
The message serves two purposes:

1. It identifies the field as a Formula Field. Formula fields in Salesforce are automatically calculated by Salesforce based on a defined formula expression. They are not manually editable by users, which is why the field appears greyed out during editing.
2. It indicates that the displayed value is not yet final. When a record is in edit mode, the formula may depend on values from other fields that have been changed but not yet saved. The formula will recalculate and display the updated result after the record is saved.

What to Expect After Saving

After saving the record, the "This field is calculated upon save" message will disappear and the formula field will display its updated, recalculated value based on the saved record data. No action is required to dismiss the message — it is automatically hidden once the record exits edit mode.