Prompt Enhancement Produces Unrelated Generations in LTX-2.5 ComfyUI Workflow
I'm testing LTX-2.5 Distilled using the official/new ComfyUI Text to Video (LTX-2.5) workflow.
First, thank you for releasing LTX-2.5. The generation speed and visual quality have been very impressive on my RTX 5070 Ti, especially at 1280×720. I've produced some excellent landscapes, product shots and human close-ups.
However, I think there may be a problem with the prompt enhancement path in the current ComfyUI workflow.
I can reproduce cases where enabling Prompt Enhancement causes the generated video to become almost completely unrelated to the original prompt.
Example 1
Prompt:
“Cinematic aerial view of a winding mountain road at sunrise, thick morning fog drifting slowly between pine-covered mountains, warm sunlight breaking through the clouds and illuminating the valley, a single red sports car driving smoothly along the empty road, gentle camera movement, realistic atmospheric depth, natural lighting, photorealistic cinematic footage, sharp detail.”
Prompt Enhancement OFF:
The result correctly contains an aerial mountain landscape, winding road, sunrise/fog and a red car. Prompt adherence is very good.
Prompt Enhancement ON:
The result instead shows a close-up cinematic scene of a man and woman standing outdoors. The requested road, car and aerial landscape are absent.
I also reproduced a similar issue with a harmless cartoon prompt.
Example 2
Prompt requested an orange cartoon cat chasing a small blue bird through a colorful kitchen.
Prompt Enhancement OFF:
The generated video contains the cat, bird and kitchen as requested, although the animal motion has some problems.
Prompt Enhancement ON:
The generated video instead shows a photorealistic person hiking/walking through a forest.
My current ComfyUI setup:
- LTX-2.5 22B Distilled transformer
- 1280×720
- 24 FPS
- 10-second generation
- LTX-2.5 video VAE conv BF16
- LTX-2.5 latent spatial upscaler
- Gemma 4 12B LTX-2.5 text encoder
gemma4_e2b_it_bf16.safetensorsas the prompt enhancement model
Disabling Prompt Enhancement consistently gives me much better adherence to the original prompt.
I'm happy to provide the workflow, exact model filenames, seeds, prompts, screenshots or generated videos if they would help reproduce the issue.
Is this expected behavior with the current prompt enhancer, or could there be an issue with the ComfyUI integration/model configuration?
it not their fault, blame ComfyUI, depending on settings ComfyUI freaks and the LLM outputs no text, you can check it with the preview text node.
So when you turn of prompt enhancement if works because it has a prompt.
When the LLM fails in it has zero prompt.
So totally expected.