Currently, public sub counts are abbreviated in most but not all places across YouTube. In August, we’ll make this more consistent by always showing abbreviated sub counts publicly. Creators: You’ll still see your full sub count in Studio! Learn more → http://yt.be/help/abbrev-count …pic.twitter.com/pmaKk4EU4k
You were never able to see it physically go up and down unless you use third-party sub counts because YouTube has always only updated the counter on their website every hour or so. also I bet they did this to make more people use the youtube api instead of web scraping lmao