Yeah. With newer games, records are constantly getting smashed because new exploits are found almost daily. Kinks are ironed out and new routes are formed. You're pretty much just paving the way for a newer, faster run until major skips have been found and it settles down a bit.
If Crypt Keeper is playing constantly and learning new skips, he could at least stay in the top 5, but I have a feeling he got his WR and then sat there going "I did it, I'm your Speed Goddess" until someone killed a boss faster.