It does sound like a set-up issue... probably bridge and truss rod and maybe the nut too. For whatever reason you got one that really needed a set up. Or it may have left the warehouse OK and then sat in a baking hot UPS truck or high humidity from floods and storms or both for a few days and the wood moved like crazy. Regardless of whether it left their warehouse that way or reacted to the weather during shipping, it is an issue.
Reach out to Sire and find out how things get paid for under warranty and do that or return it and either get a replacement or take your money and look at something else. Unfortunately if you return it, you'll be out shipping costs. Don't putz around though as your window to return the bass is 30 days. If you decide to take it to a repair person, choose a good one (ie, don't take it to your local GC) or you could end up with things being worse than when you started. Perhaps if you tell us where you're located, some folk may have recommendations for good repair people
Do not regret returning the G5123B at ALL. Will need to make a Neck adjustment. Fret buzz reduction required. WARNING NEWBIE QUESTION. First instrument with the hex nut adjustment at the bridge not the nut. Does Lefty Loosy hold the same for Truss adjustment made at the bridge? (Counterclockwise, i.e. Relief, decrease the bow/straighten the neck and Clockwise, Righty Tighty, increase the bow in the neck, {I try to remember it as the head curving closer to the bridge}) Which brings me to ask...
