I'm not sure when it first started, but it was sometime this year. My reading list is randomly deleting novels without my consent. I don't know if this is a NU problem or if it's the Notifications for NovelUpdates app problem, since I mostly read from it. Some novels don't get updated and when I search for them, they're not on my reading list anymore. I don't know why this is happening. There's also the bugged latest chapters that redirect me to an entirely different novel when I click on them (doesn't happen with every novel) and the chapters that won't mark as read even after trying to a bunch of times (like My Son is the Villain, which is bugged at ch29 and doesn't mark ch30 as read no matter how many times I refresh the NU page on my browser). Would really appreciate some help in not missing any more updates of my favorite novels.
first of all, Novel Updates does not have an app. if you're using any, they're not officially by Novel Updates, nor are they supported by Novel Updates. secondly, your issue IS very likey related to the usage of the said app. The admin updated NU's security-related stuff recently, and the app(s) were not able to cope with it. 99% of recent reports we got regarding; novels disappearing chapters not being able to be updated novels duplicating itself novels could not be deleted/moved were all related to the usage of 3rd-party app(s). There's nothing much we can help you about that. You should bring the issue to the app's creator instead.