Assuming the knife initially was snapping shut OK and then suddenly changed, here are a couple of possibilities that've been reported on occasion:
Case knives have occasionally been known to have some grit or buffing/polishing debris in their pivots, upon leaving the factory. That swarf/grit can make the joints pretty sticky or gummy, especially when mixed with some oil, which gets it kind of 'muddy'. The fix for that is usually a good cleaning, exercising the pivots while immersed in some soapy water (using liquid dish soap), to work the grit out of the joints. Rinse under hot water, to evaporate off most of the residual moisture, then wipe it down and re-lube everything again.
Another possibility might be some burrs on the edges of the ricasso or tangs of the blades, which create friction against the liners upon closing and can contribute to 'sticky' joints, or joints that don't have a lot of snap in them. Might feel for those on the edges of the tangs, and/or visually inspect under brightly-lit magnification. If any burrs are found, they can usually be burnished off using something like a ceramic hone, or some relatively high-grit sandpaper (800+).
One issue I've occasionally had, with some of my own knives, is just some pocket lint getting stuck in the pivots, and making them hang up or not close fully on their own. The fix for that is the same as mentioned for the swarf/grit, giving it a good bath and exercising the pivots while it's immersed.
If, on the other hand, the pivot is just loose and seems to have no pull at all, to hold the blade closed, I'd send that one back to the dealer (SHC) for replacement. I'd be surprised if they weren't willing to deal with it themselves. I don't think you'd need to send it to the factory, UNLESS you otherwise like the specifics of this particular knife and want to keep it, after it's properly repaired. Then, Case should be able and willing to do that for you.
