Illustrator script loop through sub-layers adjusting visibility to export each layer with artboard a

I have a layer in Illustrator that contains 48 sub-layers. Very simply, I want to loop the sub-layers, make each visible, export it as a PNG, then make it hidden, then move on. It works great for about half of the layers and I can't find any explanation why. Some of the sub-layers have a bunch of paths, some have a <Group> with paths, some have a named group with paths (i.e. 'logo') and some have two named groups, one hidden one visible. In any case - some that appear to have the same structre export as others that export a blank image. 

The visibility error report comes up empty and the visibility report, below... suggests every layer is shown then hidden correctly.... 

I wish I could just export for screens and assets panel, but you can't do that using the artboard and I need all images the same dimensions, so i'm really stuck.

edgewater_combo - blank

edgewater_logo - exported

everglades - exported

feadship -  blank

ferretti_logo - exported

ferretti - blank

var doc = app.activeDocument;

// Specify the target layer name
var targetLayerName = "FACE3W"; // Replace with your target layer name

// Specify the prefix for the filenames
var prefix = "FLAT_FACE3W_"; // Replace with your desired prefix

// Function to pause execution for a given time in milliseconds
function sleep(ms) {
    var start = new Date().getTime();
    while (new Date().getTime() < start + ms);
}

// Find the target layer
var targetLayer = null;
for (var i = 0; i < doc.layers.length; i++) {
    if (doc.layers[i].name === targetLayerName) {
        targetLayer = doc.layers[i];
        break;
    }
}

if (targetLayer) {
    alert("Target layer found: " + targetLayer.name);

    // Collect all items within the target layer
    var subLayers = [];
    var items = targetLayer.pageItems;
    var layerItems = targetLayer.layers;

    // Add sub-layers
    for (var i = 0; i < layerItems.length; i++) {
        subLayers.push(layerItems[i]);
    }

    // Add group items
    for (var j = 0; j < items.length; j++) {
        if (items[j].typename === "GroupItem") {
            subLayers.push(items[j]);
        }
    }

    alert("Total sub-layers found: " + subLayers.length);

    // Initialize report strings
    var visibilityReport = "";
    var visibilityErrorReport = "";

    // Get the count and names of sub-layers
    var subLayerCount = subLayers.length;
    var subLayerNames = "";
    for (var i = 0; i < subLayers.length; i++) {
        subLayers[i].visible = true;  // Make the sub-layer visible
        sleep(100);  // Pause to ensure the change takes effect
        if (subLayers[i].visible) {
            visibilityReport += subLayers[i].name + " is now visible\n";
        } else {
            visibilityErrorReport += subLayers[i].name + " could not be made visible\n";
        }
        subLayerNames += subLayers[i].name + " (" + subLayers[i].typename + ")\n";

        // Export the file
        var file = new File(doc.path + '/' + prefix + subLayers[i].name + '.png');
        var exportOptions = new ExportOptionsPNG24();
        exportOptions.antiAliasing = true;
        exportOptions.transparency = true;
        exportOptions.artBoardClipping = true;
        doc.exportFile(file, ExportType.PNG24, exportOptions);

        subLayers[i].visible = false; // Hide the sub-layer again
        sleep(100);  // Pause to ensure the change takes effect
        if (!subLayers[i].visible) {
            visibilityReport += subLayers[i].name + " is now hidden again\n";
        } else {
            visibilityErrorReport += subLayers[i].name + " could not be hidden again\n";
        }
    }

    // Compile the final report
    var finalReport = "Total sub-layers found: " + subLayerCount + "\n\nNames of sub-layers:\n" + subLayerNames;
    finalReport += "\n\nVisibility Report:\n" + visibilityReport;
    finalReport += "\n\nVisibility Error Report:\n" + visibilityErrorReport;

    // Display the final report
    alert(finalReport);
} else {
    alert("Layer '" + targetLayerName + "' not found.");
}