limit ILL form caches to session

src/Form/RoblibIllLoanForm.php

@@ -145,6 +145,7 @@ class RoblibIllLoanForm extends FormBase {
     $config = \Drupal::config('upei_roblib_ill.settings');
     $form['#prefix'] = '<div id="upei-roblib-ill-request-form">';
     $form['#suffix'] = '<div class="roblib-required">* = Required Field</div></div>';
+    $form['#cache']['contexts'][] = 'session';
     $type = upei_roblib_ill_get_request_variable('genre');
     $genre = empty($type) ? 'article' : $type;
     $form['Genre'] = [
@@ -361,6 +362,7 @@ Freedom of Information and Protection of Privacy Act and will be protected
  and providing library service. Direct any questions about this collection to
   Health Sciences and Scholarly Communications Librarian at ill@upei.ca, 550
    University Ave, Charlottetown PE , 902-566-0453.</div>';
+    $form['#cache']['contexts'][] = 'session';
     $form['FirstName'] = [
       '#type' => 'textfield',
       '#title' => t('Your First Name'),