Incomplete response when using incremental rendering

Testing #311090

I ended up in this state, where the response finished but didn't show everything:

<img width="928" height="277" alt="Image" src="https://github.com/user-attachments/assets/a234ff6c-51a0-46a0-866f-db6b68f9da28" />

Settings:
<img width="487" height="291" alt="Image" src="https://github.com/user-attachments/assets/751a6bfa-026e-4c5a-a18c-878483eaccf4" />