diff --git a/src/diffusers/pipelines/modular_pipeline.py b/src/diffusers/pipelines/modular_pipeline.py
index 92cb50a8b4..97a8677bda 100644
--- a/src/diffusers/pipelines/modular_pipeline.py
+++ b/src/diffusers/pipelines/modular_pipeline.py
@@ -1033,16 +1033,17 @@ class SequentialPipelineBlocks(ModularPipelineMixin):
     def _traverse_trigger_blocks(self, trigger_inputs):
         # Convert trigger_inputs to a set for easier manipulation
         active_triggers = set(trigger_inputs)
-
         def fn_recursive_traverse(block, block_name, active_triggers):
             result_blocks = OrderedDict()
             
-            # sequential or PipelineBlock
+            # sequential(include loopsequential) or PipelineBlock
             if not hasattr(block, 'block_trigger_inputs'):
                 if hasattr(block, 'blocks'):
-                    # sequential
-                    for block_name, block in block.blocks.items():
-                        blocks_to_update = fn_recursive_traverse(block, block_name, active_triggers)
+                    # sequential or LoopSequentialPipelineBlocks (keep traversing)
+                    for sub_block_name, sub_block in block.blocks.items():
+                        blocks_to_update = fn_recursive_traverse(sub_block, sub_block_name, active_triggers)
+                        blocks_to_update = fn_recursive_traverse(sub_block, sub_block_name, active_triggers)
+                        blocks_to_update = {f"{block_name}.{k}": v for k,v in blocks_to_update.items()}
                         result_blocks.update(blocks_to_update)
                 else:
                     # PipelineBlock
@@ -1069,13 +1070,14 @@ class SequentialPipelineBlocks(ModularPipelineMixin):
                     matching_trigger = None
                 
                 if this_block is not None:
-                    # sequential/auto
+                    # sequential/auto (keep traversing)
                     if hasattr(this_block, 'blocks'):
                         result_blocks.update(fn_recursive_traverse(this_block, block_name, active_triggers))
                     else:
                         # PipelineBlock
                         result_blocks[block_name] = this_block
                         # Add this block's output names to active triggers if defined
+                        # YiYi TODO: do we need outputs here? can it just be intermediate_outputs? can we get rid of outputs attribute?
                         if hasattr(this_block, 'outputs'):
                             active_triggers.update(out.name for out in this_block.outputs)