Yeah this happens to me too. Bc I think there was a update or something and it added that you can see what chapters you’ve read and which ones you haven’t. But if the last time you read it was before the update it won’t keep track of what chapter your at. (I think, I’m not sure)
It never happened to me, but here's a tip: when a series that is not often uptaded gets a new chapter, I always re-read the one that was updated before the new chapter. And to see what chapter is new you just need to check the date that it was uploaded!! Hope your problem gets fixed soon! :)
This is why I always write which chapter I’m on when I put it in the reading section because this has happened to me lol.
I can't be the only one experiencing this. So, ofc i have hundreds of manga etc that in reading right now and i don't read them all the time. As a result of that i have noticed that when i get updates from said manga that i haven't seen update in a WHILE bc i have so many, that when i click on the update i see chapters i haven't read before. So I'm like" Hm, okay cool, just needa scroll down and catch up" right? Well..funny thing about that is, heh, IT SAYS I HAVEN'T READ ANY CHAPTERS AT ALL BEFORE AND NOW I HAVE NO IDEA WHERE I LEFT OFF BC OF HOW MANY MANGA IM KEEPING TRACK OF!!! This has happened to me too many times to count now, and I've started to drop series because they have hundreds if chapters released already and im not about to scroll through all that to find where i was...T^T