As of 4D v19, the Outside data file storage option is no longer supported for object type fields. If this option was selected for an object field, it is automatically converted to In data file and used for new records. Existing data in object fields is transparently rewritten at the new location when the parent record is saved. To force all records to be rewritten at once, you can compact the data file with the "Update records" option.

For more information (see Stored in record, data file or outside data file)
https://doc.4d.com/4Dv19R7/4D/19-R7/Field-properties.300-6013520.en.html#5523008