I feel this in my bone. Readers are basically reading my first draft, and I am a discovery writer, trying to keep the story consistent is so hard. I have to constantly check what I wrote previously to make sure it meshes well with what I'm writing.It was pretty minor, but I went and changed something and forgot about it, so I had characters like ten chapters later referencing a conversation that never happened. Oops. You need a ledger or something to keep track of everything sometimes.
A simple example, I keep forgetting whether I called the place my MC and his friends hang out a pub or a tavern. It's a fantasy novel, so tavern works better, but I called it a pub and now I'm stuck with pub lol.
The other big thing is character traits. I don't describe much, but on the rare occasions I do, I need to check back to see height, hair color and whatnot.
All these things could be solved with a decent story outline, but I'm that type of person that writes an outline then completely loses interest in the story, so I make outlines as I go, but procrastination has all but ensured I outline as little as I can get away with.
As for plot holes, I caught it while editing so my readers were saved, but a character I said was dead was alive teaching my MC how to use an axe. That would've been really embarrassing had I uploaded that part without editing.