I keep meaning to bring this to your attention.
Steps to reproduce:
Using the CSpace UI, enter a collection date for an object.
Observe that the CSpace UI has parsed that date into beginning and ending month, day, and year, and then save the cataloging record.
Use the OIR web app ("Place and Date" field set) for a range of objects that includes the just-edited object.
Edit the collection dates of one or more objects in this range (but do not edit anything about the just-edited object.
Submit the changes via the OIR web app.
Open the originally edited object and note that the scalar date fields have been set to NULL for the date, despite no changes having been made to the date.