Ah......Creation of all things.
It is "said" that is deflects all things. It's Legend in the canon, not FACT. If the Yata Mirror doesn't have Senjutsu infused as well, could it withstand the Truth Seeking Balls? I have a hard time believing that.
All in all I do believe the Yata Mirror CAN deflect any and all other Techs....provided the techs aren't Senjutsu infused....probably. Maybe? There is no evidence to the contrary or to confirm. Except for the fact that it is "Said" in the written material. What people "say" is not necesarily the truth of the matter. Many embellishments are attributed to things that are way more mediocre than what we may think...or what they KNOW.
The Yata mirror is a Legendary object/jutsu. Much of the facts about the thing is more "legend" than what is known as real Fact (this is speaking In Fiction). Like the Sage himself. Not much is known about him, except for what people "say"...that was until l -WE- (the audience) were shown more about him, but that doesn't mean that the people/populace knows more.
Okay......I've said more than enough about this crap.