diff --git a/generic/forms.py b/generic/forms.py
index 1c95620d..613ca8a8 100755
--- a/generic/forms.py
+++ b/generic/forms.py
@@ -828,10 +828,11 @@ class UserAutocomplete(ModelAutocomplete):
     search_attrs = ["first_name", "last_name", "username"]
 
 class UsersAutocompleteForm(Form):
-    users = ModelChoiceField(queryset=User.objects.all(), widget=AutocompleteWidget(
-        ac_class=UserAutocomplete, options={"multiselect": True}
-
-    ))
+    # Use a ModelMultipleChoiceField so the widget's multiselect option maps to a multi-value field
+    users = ModelMultipleChoiceField(
+        queryset=User.objects.all(),
+        widget=AutocompleteWidget(ac_class=UserAutocomplete, options={"multiselect": True}),
+    )
 
 autocomplete_register(UserAutocomplete)
 
diff --git a/generic/templates/generic/user_form_fixed.html b/generic/templates/generic/user_form_fixed.html
new file mode 100644
index 00000000..012d988c
--- /dev/null
+++ b/generic/templates/generic/user_form_fixed.html
@@ -0,0 +1,21 @@
+{% load crispy_forms_tags %}
+
+{{ form.media }}
+<form hx-post="{% url 'generic:exam_collection_add_author' collection_id %}" hx-target="#add-user" hx-swap="innerHTML" hx-indicator="#add-author-indicator" action="" method="post" enctype="multipart/form-data" id="user-form" class="inline-form">
+    {% csrf_token %}
+
+    {{ form|crispy }}
+    {% comment %} Use a normal submit so the form data is included in the HTMX request {% endcomment %}
+    <button type="submit" class="btn btn-primary">Submit</button>
+
+    <span id="add-author-indicator" class="ms-2" aria-hidden="true">
+        <span class="spinner-border spinner-border-sm" role="status" aria-hidden="true"></span>
+    </span>
+
+</form>
+
+<style>
+    /* Hide indicator by default; HTMX will add the `htmx-request` class during requests */
+    #add-author-indicator { display: none; }
+    #add-author-indicator.htmx-request { display: inline-flex; align-items: center; }
+</style>
diff --git a/generic/views.py b/generic/views.py
index 2bba6213..f1ea4cfe 100644
--- a/generic/views.py
+++ b/generic/views.py
@@ -5165,9 +5165,10 @@ def exam_collection_add_author(request, collection_id):
     if request.method != "POST":
         form = UsersAutocompleteForm()
 
+        # Render the fixed form which properly includes form data in HTMX POSTs
         return render(
             request,
-            "generic/user_form.html",
+            "generic/user_form_fixed.html",
             {"form": form, "collection_id": collection_id},
         )
         return