I think the reason for both of these things is because Wildbow has had trouble ordering the chapters the way he wants them in the ToC. If you’re just clicking next to get to each chapter, then eventually the interludes will show up like this (for example): Interlude 10 (Donation Bonus), Interlude 10 (Donation Bonus #2), Interlude 10 (Donation Bonus #3), Interlude 10.
Huh, interesting. I guess his TOC is somewhat automated, then?
But yeah, I click next chapter each time.
(Speaking of which, I’ve just found out what caused my Worm tab to go back to Interlude 8 a couple days ago. The good news is it’s preventable (or rather, updatable). The bad news is I realized it because it happened again, so that’s another round of clicking through two Arcs’ worth of chapters to get where I’m supposed to be. :p)