Crow Feathers on the map but nothing when i get there

[louis little]

Looking for crow feathers, so i scan for them and when i get there, nothing. are they falling though the floor?

[WhiteDecay]

Have you looked up? Some time they are caught on the grass, weed, rock etc. The scanner wont show what level they are on. 
If you already grabbed them it takes awhile for the scanner to reset so you have to check it. If you are looking at the map it wont update after getting them.