It never struck me as odd before, but when she and Cat Noir are up against the Puppeteer-controlled Lady Wifi in Marinette's room, Ladybug is perfectly calm about Cat Noir and Lady Wifi being in her room. That is, right up until Cat Noir sends a Pause to a magazine cover of Adrien. She then panics and rushes to kick Cat Noir out of the room to destroy the wifi antennae, directing his attention elsewhere. Right after he takes the order and leaves, its like it neer happened. It's this sudden change that I find so peculiar.
Why does she not want Cat Noir to see the fact that she's got pictures of Adrien in her room? She clearly doesn't mind when other people except Adrien do. She has the same reaction to attention being drawn to the picture as she does in "The Gamer" when Adrien comes over and she forgot to take care of a picture of him. Does she know, subconciously, that he's Adrien? Or does she think Cat Noir will make fun of her? Is it both?
I guess Marinette likes her privacy? Maybe she doesn't want to give Cat Noir any reason to tease her from the stuff on her room if they cross paths again, or perhaps she doesn't want Cat Noir to be in such a place linked to her and have any reason to gets suspicion that she and Ladybug and one in the same.
Watching the scene again, it probably comes down to two reasons over Marinette not wanting Cat Noir to see her room. The first is that Ladybug didn't want her precious photos of Adrien being ruined, but that seems ridiculous, the pause button causing little harm to any objects like the. The second and more plausible reason is that Ladybug remembers how dangerous a villain that Lady Wifi is. If either of them got hit with a pause or lock button and didn't destroy Lady Wifi's source of energy in time, the Puppeteer would easily win. Cataclysm is better for quickly destroying the wifi connection than Ladybug's yo-yo or Lucky Charm, so I think that's why Ladybug instantly sends a reminder to Cat Noir about how to depower Lady Wifi and lets him go for it instead of going for it herself.
There may not much of a reason, either; there just may have been the need to make the story move along, and the actions come off as weird because of it.
She says she doesn't want him poking around her room, but her tone is light and playful about the idea. It isn't until she remembers about the pictures of Adrein she has that she freaks out. It's just how she seemed alarmed but calmed down when he left I found peculiar. It felt more like an excuse to get him out of the room, since she doesn't usually panic like that during akuma fights. Normally, she would have spoken with her usual light, authorative tone she usually uses when giving a direction to Cat Noir. I mean, maybe I'm just being weird about it myself.
I guess she just wants no one to know except Alya.
That was just in case someone hasn't seen the episode Gigantitan. When she's talking with the girls in her room, she freaks out when she realizes that they all already know about her crush on him. (lol) Also she finds it even more terrifying when a guy knows, even if it's not Adrien himself. In Animan, she freaked when Nino said he knew she had a crush on someone, showing that she obviously didn't want anyone else to know. Plus I can speak from expierence: I want as little people as possible to know I have a crush on someone... but mentioning that here doesn't count because no one here has ever met me in person lol.