修复添加节点bug

service/src/main/java/com/dayou/service/workflow/WorkNodeServiceImpl.java

@@ -85,7 +85,7 @@ public class WorkNodeServiceImpl extends ServiceImpl<WorkNodeMapper, WorkNode> i
                 return this.update(new LambdaUpdateWrapper<WorkNode>().set(WorkNode::getPriviousNodeId, nodeId).eq(BaseEntity::getId, ex.getId()));
             }
         } else {
-            WorkNode ex = this.getOne(new LambdaQueryWrapper<WorkNode>().isNull(WorkNode::getPriviousNodeId));
+            WorkNode ex = this.getOne(new LambdaQueryWrapper<WorkNode>().isNull(WorkNode::getPriviousNodeId).eq(WorkNode::getFlowId,workNode.getFlowId()));
             if (ex != null && ex.getFlowId().equals(workNode.getFlowId())) {
                 Long nodeId = saveNodeAndTask(workNode);
                 return this.update(new LambdaUpdateWrapper<WorkNode>().set(WorkNode::getPriviousNodeId, nodeId).eq(BaseEntity::getId, ex.getId()));