Depending on whether or not author throws in something to hold them up. Remember Sister & Maid "just happened" to stumble across and taking care of the very assassin after MC. That can cause who knows what kind of mischief and detours.
I can not for the life of me remember any of the character names lol.
Not sure it's the one your talking about, but Boukensha License o Hakudatsu Sareta Ossan Dakedo, Manamusume ga Dekita no de Nonbiri Jinsei o Oka Suru comes to mind.
It's got a official release so i'm not sure how much it would be updated here, but you can find it easily if you look for it.
I just find the whole "ribbon being the vessel of suddenly being able to sync them" when it didn't happen earlier kinda off. Also I can defo be wrong, I've definitely put my foot in my mouth more then a few times on these discussions lol.
last chapter, it was explained that with the ribbon as a medium that has some of his fur sewn onto it, it allows him to use magic that would not harm her should he recklessly fire it off, so it letting her magic synchronise with his would also work. Another explanation would be same element buff, they both have wind magic