Sigma doesn't post firmware updates on their web site. (At least not up until recently. Since their new lenses will have a connection to allow user updates, that will change).
What you need to do is contact their tech support, describe the problem and see if they recommend sending it in for updating. If so, they normally do it for free and pay to ship it back to you, but you pay to ship it to them.
Even though everything is "new", cleaning the contacts on the lens would be a fast, cheap way to eliminate that possible source as the cause of the problem.
I have a copy the same lens that is a few years old. It works fine on my D800e, but I don't think I've tried it in LV . Maybe tomorrow. I don not use LV except on a tripod. I don't think I can hand hold a camera steady that way.