Not sure why, but The Great Mage Returns After 4000 Years hasn't updated to the current release. It has been stuck on chapter 92 on the website but it is up to chapter 100 or the translator's page. I wasn't sure where to post this, so sorry if it doesn't belong in this thread.
They're not paywalled, not anymore. And that's probably the problem. I'm guessing they get free after X days, but the bot picks up the originally paywalled versions and they get blocked until somebody manually reports the change of state.
woopread translation's chapters are *manually submitted. and yes, it was due to their premium/members-only chapters state, which only unlocked at a later time, like @Ral mentioned. *if there are no one submitting those chapter, then obviously those chapters won't show up on NU's listing. until someone, anyone did.