That's from 2010.
edit: https://www.cnn.com/2010/TECH/social.media/09/24/facebook.ou...
You're absolutely right, thanks, my mistake trusting random URLs on HN/the internet!
So it's a bug of the "automated remediation that makes things worse" family.
This system that checks for invalid values in the cache looks like a very bad idea in the first place as in my understanding it checks things beyond "is the cache up to date?".
A short update from meta with some initial high level technical details:
https://m.facebook.com/nt/screen/?params=%7B%22note_id%22%3A...