I clicked on $\mathbb{RP}^n\times\mathbb{RP}^n$ in this title

Instead of taking me to the question, it stays on the same page but now displays this

If I click on $\mathbb{CP}^n$ instead, I go to the question itself. (Here is a link to the post: Is there an explicit description of a cobordism between $\mathbb{CP}^n$ and $\mathbb{RP}^n\times\mathbb{RP}^n$?.)

To test it use, e.g., the mentioned question in the list https://mathoverflow.net/questions/tagged/cobordism

Why is this happening and can it be fixed?