so. this is gonna seem like a rant, but hear me out:
In Kwamibuster, Marinette has Alix's stopwatch on when she puts all of the miraculouses on. BUT, the watch is Alix's so this means that:
1. Alix would have to give it to Ladybug, which is unlikely, because Timetagger and the discovery of the rabbit miraculous happens after Kwamibuster (I think), and Ladybug would have to ask for it from Alix (Marinette wouldn't be able to ask, because of her secret identity), but Tikki was stuck in Kwamibuster's sack thingy, therefore Marinette couldn't transform into Ladybug.
2. Marinette "borrowed it" from Alix, even though I'm not sure if Mari knows where Alix lives. Plus, how would she get in?
3. If Timetagger is indeed before Kwamibuster, so Alix knew her time as a Miraculous holder would come, and just entrusted it to Ladybug for the time being. Then Marinette gave it to Master Fu just in case.
4. I ranted for a long time and wasted yours (haha, time and the Rabbit miraculous), and it's just a plothole. If you don't think it's a plothole, let me know what you think. Sorry for ranting.