Too many factors to diagnose a good cause. COuld be they were seeing you even if you were still. Facemasks and gloves for everybody? Are the birds call shy? Maybe the decoys didn't look right. We went through 11 different theories to find our problem yesterday morning. Even if the ducks are still flying go out and change stuff around. If they weren't commiting before, then it does no harm and go move stuff.
It is late season here, what about there? Lots of pressure? Just keep trying different stuff when you're out there. Eventually something will work. Finding that one thing comes with experience. I have hunted these things 10 years and sometimes they make you so mad you just want to give up.