Try the latest version of the mod. It has two changes that may help in cases where ComfyUI seems to be communicating inconsistently.
- I'm using a different event to signal the end of the workflow. This may be more reliable, but I can't prove it without more data.
- There's a new "Fetch last" button that will allow you to manually fetch the output of the last prompt if you know ComfyUI has actually finished.