It's that what happened when a popular post that was 'blowing up' on Reddit went from 500 updoots on the front page to mediocre front-page posts regularly getting 3-4k updoots seemingly over night?
I was there, I remember the change, I can't remember why it happened.
It was ostensibly to make it harder for advertisers to game their own posts (similar to not showing you your own posts' scores for a set period after creation), but like everything else on that site, it's turned into some bullshit activist mods and admins use to keep things their corporate overlords don't like from gaining too much traction.