It’s so you can reread the posts you just read! It’s a feature!
And the 124 posts it jumped ahead – to save me from wasting time reading boring posts?
Yup! One of Discourse’s better features!
Abusing the astral equine here, something else I’ve noticed, I’ll post and it jumps me backwards some number of posts. While this would be merely annoying because there is a back button. It’s actually extremely annoying because the back button doesn’t actually take you back to where you were(you new post). Instead it puts you as much as ten posts before your new post, only sorta maybe kinda close to where you were. If you edit your post, no back button for you! You just get deposited somewhere near the start of the thread. Can fix?
I didn’t notice the previous thread on the topic but since this one popped up in my feed today, I’ll note that I too am experiencing this issue. I’m using Straight Dope Light theme on the latest Edge browser, Windows 10.