Today I came across an ad on this question on SO: https://stackoverflow.com/questions/58299219/how-to-replicate-vlookup-in-vba (I don't expect it to stay very long).
There was a community promotion ad on the right hand side of the site, I think for one of our English sites. It had a sentence that I only partially remember:
Idiom ... poor or even poorer
I found it interesting, so I clicked that ad. Which caused a new instance of SO to open within the ad space. Unfortunately I failed to take a screenshot. I've been refreshing the page like crazy, but can't get the ad to appear again.
Edit:
I managed to get a new community add, for the photography site, and captured a screenshot:
Edit2:
This bug still persists, I saw it today with an OOP add from CodeReview, and an area 51 add.