Issue #3525032: Scheduled transition cannot be updated in 2.0.0

src/Entity/WorkflowTransition.php

@@ -319,6 +319,8 @@ class WorkflowTransition extends ContentEntityBase implements WorkflowTransition
       case $this->getEntityTypeId() == 'workflow_scheduled_transition':
         // Create, update a scheduled transition.
         // Avoid custom actions for subclass WorkflowScheduledTransition.
+        // @todo Update existing WST, do not dicard existing and create new one.
+        WorkflowEntityHooks::deleteTransitionsOfEntity($entity, 'workflow_scheduled_transition', $field_name);
         $result = parent::save();
         break;