Self explanatory, with the "grey number" being the number on the Bungou Stray Dogs thread in the picture while the rest are "blue numbers".
I think blue numbers are "you haven't read this many posts in this thread and you haven't even loaded the thread" and grey numbers are "you haven't read this many posts in the thread but you've already loaded the thread before and you probably just went back and didn't pass by them".
i can confirm, it is pretty much this
however, u can also think of it like this. blue = new posts that are unread, gray = old posts that are unread. this accounts for times when u have both blue and gray post counts.
Yeah that pretty much covers it. Grey also happens if you scroll down too fast.
Your mouse icons were interfering with my brain.
nope... just playing match up the cursor...