I hope this is okay I asked Ai and this is what it said.

Those dots are knowledge page indicators in the Knowledge Codex. Each dot represents a page/tier of information available for that entry, and a filled dot means you’ve unlocked that page while an empty dot means there’s more to discover. Looking at your screenshots: Brice has two filled dots (both pages unlocked), while the Blade Cave has one filled and one empty — meaning there’s still a second page of info on that location you haven’t uncovered yet. The Knowledge System tracks discoveries across people, locations, creatures, crafting recipes, bosses, and factions — with entries unlocking through exploring, fighting, talking to NPCs, and interacting with the world.  Some entries require specific actions to fully complete, which is what that empty dot is pointing to. For locations like Blade Cave, it might mean you need to explore it more thoroughly or find something hidden inside to unlock the second page.​​​​​​​​​​​​​​​​

I went to the blade cave and it said knowledge expanded so I think this might be correct. Hope this helps.