diff --git a/htdocs/core/class/commonobject.class.php b/htdocs/core/class/commonobject.class.php
index e99a7bbac32..18f71ac2f20 100644
--- a/htdocs/core/class/commonobject.class.php
+++ b/htdocs/core/class/commonobject.class.php
@@ -8739,7 +8739,14 @@ abstract class CommonObject
 			$classname = $InfoFieldList[0];
 			$classpath = $InfoFieldList[1];
 			if (!$validate->isFetchable($fieldValue, $classname, $classpath)) {
-				$this->setFieldError($fieldKey, $validate->error);
+				$lastIsFetchableError = $validate->error;
+
+				// from V19 of Dolibarr, In some cases link use element instead of class, example project_task
+				if ($validate->isFetchableElement($fieldValue, $classname)) {
+					return true;
+				}
+
+				$this->setFieldError($fieldKey, $lastIsFetchableError);
 				return false;
 			} else {
 				return true;
diff --git a/htdocs/core/class/validate.class.php b/htdocs/core/class/validate.class.php
index 02ed867a5d8..1c1a895aa2a 100644
--- a/htdocs/core/class/validate.class.php
+++ b/htdocs/core/class/validate.class.php
@@ -335,4 +335,20 @@ class Validate
 		}
 		return false;
 	}
+
+	/**
+	 * Check for all values in db for an element
+	 * @see self::isFetchable()
+	 *
+	 * @param integer  $id of element
+	 * @param string $element_type the element type
+	 * @return boolean Validity is ok or not
+	 * @throws Exception
+	 */
+	public function isFetchableElement($id, $element_type)
+	{
+		// TODO use newObjectByElement() introduce in V20 by PR #30036 for better errors management
+		$elementProperty = getElementProperties($element_type);
+		return $this->isFetchable($id, $elementProperty['classname'], $elementProperty['classpath'].'/'.$elementProperty['classfile'].'.class.php');
+	}
 }
diff --git a/htdocs/core/db/DoliDB.class.php b/htdocs/core/db/DoliDB.class.php
index ea6ad2dcb7b..8895cdf83ec 100644
--- a/htdocs/core/db/DoliDB.class.php
+++ b/htdocs/core/db/DoliDB.class.php
@@ -201,8 +201,10 @@ abstract class DoliDB implements Database
 				$this->transaction_opened++;
 				dol_syslog("BEGIN Transaction".($textinlog ? ' '.$textinlog : ''), LOG_DEBUG);
 				dol_syslog('', 0, 1);
+				return 1;
+			} else {
+				return 0;
 			}
-			return (int) $ret;
 		} else {
 			$this->transaction_opened++;
 			dol_syslog('', 0, 1);