Fix crashes on *-once elements when called at bad timings

core/static/bundled/core/components/include-index.ts

@@ -84,8 +84,12 @@ const refreshElement = <
       return;
     }
 
+    // This might be called at some bad timing
+    // This prevents crashes of the observer
+    if (element.refresh) {
       element.refresh();
     }
+  }
 };
 
 // Since we need to pause the observer, we make an helper to start it with consistent arguments
@@ -130,7 +134,7 @@ startObserver(observer);
 export class LinkOnce extends elementOnce("link") {
   getElementQuerySelector(): string {
     // We get href from node.attributes instead of node.href to avoid getting the domain part
-    return `link[href='${this.node.attributes.getNamedItem("href").nodeValue}']`;
+    return `link[href='${this.node.attributes.getNamedItem("href")?.nodeValue}']`;
   }
 }
 
@@ -142,6 +146,6 @@ export class LinkOnce extends elementOnce("link") {
 export class ScriptOnce extends inheritHtmlElement("script") {
   getElementQuerySelector(): string {
     // We get href from node.attributes instead of node.src to avoid getting the domain part
-    return `script[src='${this.node.attributes.getNamedItem("src").nodeValue}']`;
+    return `script[src='${this.node.attributes.getNamedItem("src")?.nodeValue}']`;
   }
 }

core/templates/core/widgets/autocomplete_select.jinja

@@ -3,7 +3,7 @@
     <script-once type="module" src="{{ js }}"></script-once>
   {% endfor %}
   {% for css in statics.css %}
-    <link-once rel="stylesheet" type="text/css" href="{{ css }}" defer></link-once>
+    <link-once rel="stylesheet" type="text/css" href="{{ css }}"></link-once>
   {% endfor %}
 
   <{{ component }} name="{{ widget.name }}" {% include "django/forms/widgets/attrs.html" %}>