I'll offer no explanation, just three charts for the following streams
https://vrabi.net/video/fetc0Exwa8M :: Kaida Haru 3D
https://vrabi.net/video/0yUvt7LmXXs :: Nagao Kei 3D
https://vrabi.net/video/BB2zYMB-1G4 :: Flare 3D
All three are 3D streams, all three slightly below 70k.
Again, I offer no explanation for what happened but they surely are different