They leak.
Ours dont…faulty 1?
I think that the suggestion was that when tipped over, the straw has no gasket or special connection that prevents it from just leaking a bit past the lid…
I have one of these, largely because I have just been trying to find my favorite out of several styles of water bottles. And while the insulation factor is top notch, I have found that I prefer a few others for that particular leaking factor. BruMate, for instance, has the Era design, which has an integrated silicone straw, which can be rotated within a part of the lid to completely stop any liquid from coming out. And it’s good enough for literally shaking it upside-down, or dumping into a bag alongside a laptop or other electronics. Or for some occasions, I like the insulated CamelBak Eddy, which is pretty similarly insulated, but the straw is internal, with a little flip-up “bite valve” top, which also refuses to leak. I use a medium sized one of these for travel, since it fits the best in my cup holders, given that the handle portion is on top, and not the side.
So, not knocking the Stanley overall - But it does have some potential to leak if tilted over, or overturned. But for around the house, I still like mine.