diff --git a/htdocs/compta/facture/class/facture.class.php b/htdocs/compta/facture/class/facture.class.php
index d1246c13bb6..9203162bd12 100644
--- a/htdocs/compta/facture/class/facture.class.php
+++ b/htdocs/compta/facture/class/facture.class.php
@@ -519,8 +519,11 @@ class Facture extends CommonInvoice
 
 			// Define some dates
 			$originaldatewhen = $_facrec->date_when;
-			$nextdatewhen = dol_time_plus_duree($originaldatewhen, $_facrec->frequency, $_facrec->unit_frequency);
-			$previousdaynextdatewhen = dol_time_plus_duree($nextdatewhen, -1, 'd');
+			$nextdatewhen = null; $previousdaynextdatewhen = null;
+			if ($originaldatewhen) {
+				$nextdatewhen = dol_time_plus_duree($originaldatewhen, $_facrec->frequency, $_facrec->unit_frequency);
+				$previousdaynextdatewhen = dol_time_plus_duree($nextdatewhen, -1, 'd');
+			}
 
 			if (!empty($_facrec->frequency)) {  // Invoice are created on same thirdparty than template when there is a recurrence, but not necessarly when there is no recurrence.
 				$this->socid = $_facrec->socid;
@@ -610,9 +613,9 @@ class Facture extends CommonInvoice
 			$substitutionarray['__INVOICE_YEAR__'] = dol_print_date($this->date, '%Y');
 			$substitutionarray['__INVOICE_NEXT_YEAR__'] = dol_print_date(dol_time_plus_duree($this->date, 1, 'y'), '%Y');
 			// Only for template invoice
-			$substitutionarray['__INVOICE_DATE_NEXT_INVOICE_BEFORE_GEN__'] = dol_print_date($originaldatewhen, 'dayhour');
-			$substitutionarray['__INVOICE_DATE_NEXT_INVOICE_AFTER_GEN__'] = dol_print_date($nextdatewhen, 'dayhour');
-			$substitutionarray['__INVOICE_PREVIOUS_DATE_NEXT_INVOICE_AFTER_GEN__'] = dol_print_date($previousdaynextdatewhen, 'dayhour');
+			$substitutionarray['__INVOICE_DATE_NEXT_INVOICE_BEFORE_GEN__'] = (isset($originaldatewhen) ? dol_print_date($originaldatewhen, 'dayhour') : '');
+			$substitutionarray['__INVOICE_DATE_NEXT_INVOICE_AFTER_GEN__'] = (isset($nextdatewhen) ? dol_print_date($nextdatewhen, 'dayhour') : '');
+			$substitutionarray['__INVOICE_PREVIOUS_DATE_NEXT_INVOICE_AFTER_GEN__'] = (isset($previousdaynextdatewhen) ? dol_print_date($previousdaynextdatewhen, 'dayhour') : '');
 			$substitutionarray['__INVOICE_COUNTER_CURRENT__'] = $_facrec->nb_gen_done;
 			$substitutionarray['__INVOICE_COUNTER_MAX__'] = $_facrec->nb_gen_max;
 
diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index cb1f0c76a86..439b13eae02 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -7923,16 +7923,22 @@ abstract class CommonObject
 
 						// Convert date into timestamp format (value in memory must be a timestamp)
 						if (in_array($extrafields->attributes[$this->table_element]['type'][$key], array('date'))) {
-							$datenotinstring = $this->array_options['options_'.$key];
-							if (!is_numeric($this->array_options['options_'.$key])) {	// For backward compatibility
-								$datenotinstring = $this->db->jdate($datenotinstring);
+							$datenotinstring = null;
+							if (array_key_exists('options_'.$key, $this->array_options)) {
+								$datenotinstring = $this->array_options['options_'.$key];
+								if (!is_numeric($this->array_options['options_'.$key])) {	// For backward compatibility
+									$datenotinstring = $this->db->jdate($datenotinstring);
+								}
 							}
 							$value = (GETPOSTISSET($keyprefix.'options_'.$key.$keysuffix)) ? dol_mktime(12, 0, 0, GETPOST($keyprefix.'options_'.$key.$keysuffix."month", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."day", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."year", 'int', 3)) : $datenotinstring;
 						}
 						if (in_array($extrafields->attributes[$this->table_element]['type'][$key], array('datetime'))) {
-							$datenotinstring = $this->array_options['options_'.$key];
-							if (!is_numeric($this->array_options['options_'.$key])) {	// For backward compatibility
-								$datenotinstring = $this->db->jdate($datenotinstring);
+							$datenotinstring = null;
+							if (array_key_exists('options_'.$key, $this->array_options)) {
+								$datenotinstring = $this->array_options['options_'.$key];
+								if (!is_numeric($this->array_options['options_'.$key])) {	// For backward compatibility
+									$datenotinstring = $this->db->jdate($datenotinstring);
+								}
 							}
 							$value = (GETPOSTISSET($keyprefix.'options_'.$key.$keysuffix)) ? dol_mktime(GETPOST($keyprefix.'options_'.$key.$keysuffix."hour", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."min", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."sec", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."month", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."day", 'int', 3), GETPOST($keyprefix.'options_'.$key.$keysuffix."year", 'int', 3), 'tzuserrel') : $datenotinstring;
 						}