diff --git a/modules/interventi/modals/firma.php b/modules/interventi/modals/firma.php
index 57a7df787..e3e02cfc1 100644
--- a/modules/interventi/modals/firma.php
+++ b/modules/interventi/modals/firma.php
@@ -192,7 +192,7 @@ echo '
 <form action="" method="post" id="form-firma" class="hide">
     <input type="hidden" name="op" value="firma_bulk">
     <input type="hidden" name="backto" value="record-list">
-    <input type="hidden" name="records" value="<?php echo implode(';', $records ?: ''); ?>">
+    <input type="hidden" name="records" value="<?php echo implode(';', $records); ?>">
 
     <div class="row">
         <div class="col-md-12">