Leaving a comment shows a pending comment box with an empty input

Testing #253045

Whenever I make a comment at the end of a PR for this TPI, I see this for 5-30 seconds:

<img width="846" alt="Image" src="https://github.com/user-attachments/assets/7abb21d2-1be0-430c-bd90-345dd8a7c5b9" />

Eventually it becomes a real comment:

<img width="843" alt="Image" src="https://github.com/user-attachments/assets/b0f3f0c4-6ac1-4b21-bdb7-4d3eb309ab84" />