Strange. That must have been one of those minor fluctuations you see all the time then. Or maybe Dr Stone got a small surge in views back on Jan 6th even though it didn't have a chapter out. The other WSJ series went down by thousands.
(Btw, did you take note just before or just after 4 PM? Because M+ only updates their views once per hour now (on the hour), so it's the same number from 3.01 to 4.00 PM and then it suddenly jumps.)
It is very weird though that minor adjustments seem to happen during the day, but the big drops took place all at once. We'll have to see if there's a mass plummet again this evening (most likely just after 4 PM GMT+1, since that's when the chapters were published).
EDIT:
Scratch that. No minor adjustments happen during the day. I just compared every single series and all of them either went up or stayed the same since yesterday evening, that can't be a coincidence.
I'm convinced now that they only remove older views once a day, at 4 PM GMT+1. Yesterday the views from Jan 6th got scrapped (read: the views that came in between Jan 6th 4 PM and Jan 7th 4 PM, most probably), so all series that had a chapter out that day dropped a lot (and Dr Stone dropped a little, but no more than on an average day).
Today, we should see a drop in views for the same series as yesterday (second day still has high numbers, usually), as well as Heart Gear, but not for Sa-chan which was on break on the 7th.
