Interesting, yeah, 2 weeks you should have seen something.
Defective product? Application?
I really like this stuff ... Bayer Advance Season long Weed Control, it comes in concentrate and also premixed with a sprayer.
Some others may not know, here in a more southern state, weeds will grow in winter as the ground doesn't freeze for more then a night or two, add to that, the southern grasses do not grow until soil temps are above 50 degrees but weeds will grow with it colder, which is pretty much all winter long.