I think this is because of really good timing, as opposed to a bug. If you noticed, Gaara does the same thing before he either attacks or uses his mystery - he uses his sand shield first. I suppose that acts as a bait, letting you think he's prepping for a standard, which allows him that window to use his mystery instantly should you be non-the-wiser. Though, this is a theory.

That assumption was weird, but alright. I don't use Gaara much, if not at all. I tossed in my personal take on the subject, as I said prior - I assume this stems from his personal mechanics.

I think you're reacting to this a bit too hasty, he's easy to stop. You don't have to use someone who has an interupt, there's many other ninja who can do the same job if not better. It's all about using a form of strategy. I've beaten plenty of Gaara's. He's strong, yeah - but comparing him to Minato seems a bit off.