Both me and my wife are playing on PC, steam. Im hosting and can build, place etc(all works as in singelplayer game). But for her, she can only see the blueprints(even though she places the materials and it gets buildt). I can see everything she builds as normal, when i relocate it, it appears for her. When she logs out and in again, its "fixed", but only the pieces she has placed and buildt. When she places a new wall, same problem again, only sees it as a blueprint and falls through it while i can stand on it(for her im standing midair/floating). She can see all that i build as normal, its only when she builds.(This i would guess is because im the host).

She cannot relocate blueprints to make it appear either. Have also tried shared world etc, but the problem with building consists.

I play with 3 friends, we all face this issue when we aren't the ones hosting, it's quite annoying.

I'm sorry to hear that you both have been experiencing this issue with blueprint desync for clients while playing Grounded. The team is aware of this issue and they are working on a solution for a future update. I've found that if the client player punches or strikes the blueprint after it's finished it should appear in its finished state. Hopefully this will alleviate this issue and prevent you both from having to restart the game to resync  the blueprints. 

Please feel free to contact our support time and include the following information if you run into any other issues. 

Obsidian Support

1. Platform (Xbox Console, PC Game Pass, PC Steam).
2. Multiplayer or Single Player Game (if multiplayer, can you tell us how many players in total in the game, and their platforms if known)
3. Difficulty level
4. Description of issue.
5. Last thing you did in the game before the issue occurred, if applicable.

Thanks, and have a great day!