Update pipeline.py

pipeline.py

@@ -579,8 +579,8 @@ class FluxWithCFGPipeline(DiffusionPipeline, FluxLoraLoaderMixin, FromSingleFile
         )
 
         if self.do_classifier_free_guidance:
-            prompt_embeds = torch.cat([negative_prompt_embeds, prompt_embeds], dim=0)
-            pooled_prompt_embeds = torch.cat([negative_prompt_embeds, pooled_prompt_embeds], dim=0)
+            prompt_embeds = torch.stack([negative_prompt_embeds, prompt_embeds], dim=0)
+            pooled_prompt_embeds = torch.stack([negative_prompt_embeds, pooled_prompt_embeds], dim=0)
 
         # 4. Prepare latent variables
         num_channels_latents = self.transformer.config.in_channels // 4