ComfyUI 0.27.0 + ComfyUI-GGUF 1.1.10 causes VAE patcher AttributeError after running SCAIL-2 GGUF workflow

[nuopaul-ai]

Title

ComfyUI 0.27.0 + ComfyUI-GGUF 1.1.10 causes VAE patcher AttributeError after running SCAIL-2 GGUF workflow

Environment

ComfyUI:
0.27.0

Custom node:

ComfyUI-GGUF
version: 1.1.10

Loader node:

UnetLoaderGGUF

Model:

wan2.1_14B_SCAIL_2-Q4_K_M.gguf

Workflow:

SCAIL-2 video generation workflow

Description

Using the same SCAIL-2 workflow:

• ComfyUI ver:0.25.0 works correctly
• FP16/FP8 safetensors model works correctly
• GGUF model completes inference but crashes during execution cache cleanup

The crash happens after sampling, not during model loading or denoising.

Error

AttributeError:
'VAE' object has no attribute 'patcher'

Traceback:

comfy_execution/caching.py

if not hasattr(output, "is_dynamic") or not output.is_dynamic():

comfy/sd.py

def is_dynamic(self):
return self.patcher.is_dynamic()

Reproduction

1. Load SCAIL-2 workflow
2. Replace:

UNETLoader
wan2.1_14B_SCAIL_2_fp16.safetensors

with:

UnetLoaderGGUF
wan2.1_14B_SCAIL_2-Q4_K_M.gguf

3. Run workflow

Result:

Generation starts successfully.

After execution:

AttributeError: 'VAE' object has no attribute 'patcher'

Additional information

The VAE is loaded through standard:

VAELoader
Wan2.1_vae.safetensors

The issue only appears when the UNet is loaded using:

UnetLoaderGGUF

Possible compatibility issue between:

• ComfyUI 0.27 execution cache dynamic output checking
• GGUF ModelPatcher implementation
• VAE output handling

Temporary workaround

Changing:

def is_dynamic(self):
    return self.patcher.is_dynamic()

to:

def is_dynamic(self):
    if hasattr(self, "patcher"):
        return self.patcher.is_dynamic()
    return False

avoids the crash.

However, this may not be the correct upstream fix.