Extendscript Bug writing to new metadata property in PPro 24.3.0

[BrianDavison]

I'm creating a new metadata property using addPropertyToProjectMetadataSchema and Premiere will create the property just fine, but it won't add any data into that property. 

Below is code lifted straight from the Premiere Pro github sample page.  I've tested the same exact code in 23.6.5 and it works as expected where it both creates the property and adds data to that property, but in 24.3.0 it just creates the property and won't add data to it.

Maybe I just have a setting wrong in 24.3.0, but I can't think what it would be! 

modifyProjectMetadata : function () {
		var kPProPrivateProjectMetadataURI	= "http://ns.adobe.com/premierePrivateProjectMetaData/1.0/";

		var namefield	= "Column.Intrinsic.Name";
		var tapename	= "Column.Intrinsic.TapeName";
		var desc		= "Column.PropertyText.Description";
		var logNote    	= "Column.Intrinsic.LogNote";
		var newField	= "ExampleFieldName";

		if (app.isDocumentOpen()) {
			var projectItem	= app.project.rootItem.children[0]; // just grabs first projectItem.
			if (projectItem) {
				if (ExternalObject.AdobeXMPScript === undefined) {
					ExternalObject.AdobeXMPScript	= new ExternalObject('lib:AdobeXMPScript');
				}
				if (ExternalObject.AdobeXMPScript !== undefined) {	// safety-conscious!
					var projectMetadata		= projectItem.getProjectMetadata();
					var successfullyAdded	= app.project.addPropertyToProjectMetadataSchema(newField, "ExampleFieldLabel",	2);

					var xmp	= new XMPMeta(projectMetadata);
					var obj	= xmp.dumpObject();

					// var aliases = xmp.dumpAliases();

					var namespaces					= XMPMeta.dumpNamespaces();
					var found_name					= xmp.doesPropertyExist(kPProPrivateProjectMetadataURI, namefield);
					var found_tapename				= xmp.doesPropertyExist(kPProPrivateProjectMetadataURI, tapename);
					var found_desc					= xmp.doesPropertyExist(kPProPrivateProjectMetadataURI, desc);
					var found_custom				= xmp.doesPropertyExist(kPProPrivateProjectMetadataURI, newField);
					var foundLogNote       			= xmp.doesPropertyExist(kPProPrivateProjectMetadataURI, logNote);
					var oldLogValue        			= "";
					var appendThis          		= "This log note inserted by PProPanel.";
					var appendTextWasActuallyNew	= false;
					 
					 if(foundLogNote){
						var oldLogNote = xmp.getProperty(kPProPrivateProjectMetadataURI, logNote);
						if (oldLogNote){
							oldLogValue = oldLogNote.value;
						}
					 }

					xmp.setProperty(kPProPrivateProjectMetadataURI, tapename, 	"***TAPENAME***");
					xmp.setProperty(kPProPrivateProjectMetadataURI, desc, 		"***DESCRIPTION***");
					xmp.setProperty(kPProPrivateProjectMetadataURI, namefield, 	"***NEWNAME***");
					xmp.setProperty(kPProPrivateProjectMetadataURI, newField, 	"PProPanel set this, using addPropertyToProjectMetadataSchema().");


					var array	= new Array();
					array[0]	= tapename;
					array[1]	= desc;
					array[2]	= namefield;
					array[3]	= newField;

					var concatenatedLogNotes = "";

					if (oldLogValue != appendThis){ // if that value is not exactly what we were going to add
						if (oldLogValue.length > 0){		// if we have a valid value
							concatenatedLogNotes += "Previous log notes: " + oldLogValue + "    ||||    ";
						}
						concatenatedLogNotes += appendThis;
						xmp.setProperty(kPProPrivateProjectMetadataURI, logNote, concatenatedLogNotes);
						array[4]    = logNote;
					}

					var str = xmp.serialize();
					projectItem.setProjectMetadata(str, array);

					// test: is it in there?

					var newblob		= projectItem.getProjectMetadata();
					var newXMP		= new XMPMeta(newblob);
					var foundYet	= newXMP.doesPropertyExist(kPProPrivateProjectMetadataURI, newField);

					if (foundYet){
						alert("PProPanel successfully added a field to the project metadata schema, and set a value for it.");
					}
				}
			} else {
				alert("No project items found.");
			}
		}
	},