So, it occured to me that Alix's pocket watch didn't change to different camoflauge modes when it was being passed around in timebreaker. That means that there's either some way to stop it from doing that, or it being a miraculous is a retcon.
I think it falls under the 'we didn't want to reveal this yet' category, so while technically a 'retcon' after a fashion (Just like Miraculouses being indestructible) it's not something I would complain overly about, as it was only episode 5 of season 1 of the show and a minor inconsistency. We give some leeway here.
It could also be that holding a Miraculous doesn't change it, but actively wearing it does. Therefor Someone would have to hook the Watch by it's chain onto their pocket, then it would shift forms. (It's not shown with a chain, but that's how they work)