It sometimes happens to me that when I am diving in the ocean I have seaweed that's visible, but can't be cut. I also have some shells / salts and such things that are visible and I can collect them, but they don't appear in inventory (and I don't get the collect notification on the side for them). It seems like those items are visible, but not actually there. So maybe a graphic issue?
#Ocean has visible, but not collectible items
serene ermine
vernal jungle
Hi @serene ermine , thank you for bringing this issue to our attention! We have received similar reports here: https://discord.com/channels/623097219628662784/1406779436753489930 and our team is currently in the process of checking the issue.
In the meantime, could you share a video of the Host & Guest POV of the same object the issue occurred? And if you are playing on Steam, could you share your Save File here? This will provide us with more details on the problem 
serene ermine
Gonna make the video asap.
My save file (I'm player 2) for you: