i've seen a lot of people posting about this problem, and i think it might be something to do with being logged in or not or being on mobile
Glitch, not all sites are perfect. Try report this to admin instead.
Are you on phone? If yes, here is my suggestion:
1) open your browser in incognito mode
2) log in. If you don't have an account, sign up. If you want to read manga peacefully, log in is compulsary.
3) open your manga, tick the multiple page views.
I'm using Safari on iphone, and I've never faced any problem with page not loading/duplicate pages, unless mangago server itself was having an issue.
Good luck!
What's wrong with Mangago? I keep seeing duplicate pages when I'm reading comics. It's not just one series, it's multiple of them. Pages are out of order and some of them keep repeating.