Under my Registry>Mysterious Artifacts, there is a red dot notification that won’t go away. All collected objects have been placed and I even tried out the camera option for those that had it but the red dot remains. Does anyone know why or how to make it go away?

Since you collected all the objects for that page, you can now “prestige” the page. It’s a little button in the top right corner of that page. You basically start over on that page, and start collecting those same foundables again, but you get more XP for each item.

This does not answer the OPs issue. I have a permadotted Challenges>Books. None of the book pages I to III can be prestiged. Double checked and even tapped the area to hit a possibly invisible button.
None of the books can be placed. Tapped every book to make sure it wasn’t a display bug.
The problem started after I was able to place an image while levelling up challenges at the same time.
Uninstalled the game, reinstalled. The permadot seems to be server side.l, it came back and multiplied. I now also have a permadot on achievements, but there is no achievement ready to collect.

I have exact same issue with both books in Challenge section permadot & Achievements.
It’s not a Prestige page issue either.
Cleared cache, data, didn’t work. Uninstalled & reinstalled, no dice.
Reported problem.
It’s really infuriating!

@schrodinger I was under the impression from the OP’s comment that they had placed all the objects on the page, which is why I suggested that it might need to be prestiged.

Actually it answered the question perfectly. I had the exact same red dot notification in the same registry division and once I selected the option to Prestige the items, it went away! Thanks @PennyMustard

Yes, clicking to prestige the item worked for me too! If you don’t want to prestige, click “later” and it will still go away!
I’m also having this same issue with achievements. I’ve clicked every achievement and all bonus rewards to make sure.
I’m having this issue with my CoMC section. I haven’t collected all of the items, but everything I have collected has been placed, and there’s still a notification dot. There doesn’t seem to be any advice out there for it besides those who are ready to Prestige that section.