<<After glowing reviews, I spent $200 to try it out for my research. It hallucinated 8 of 10 references on a couple of different engineeribg topics. For topics that are well established (literature search), it is useful, although o3-mini-high with web search worked even better for me. For truly frontier stuff, it is still a waste of time.>>

<<I've had the hallucination problem too, which renders it less than useful on any complex research project as far as I'm concerned.>>

These quotes are from the link you posted. There are a lot more.

I think Sabine is just wrong in this case. I don't think Deep Research can even hallucinate links in this way at all.