The symbol that represents my Layer1 only displays part of the time in the legend. If I zoom in and out sometimes I can see it flash for a split second. Layer2 displays at all times. Sometimes it will display initially and then upon zooming in it disappears. The title for Layer1 displays at all times. Both are feature layers.
var legend = new Legend({
map: map,
layerInfos: [
{
layer: Layer1,
title: "Layer One"
},
{
layer: Layer2,
title: "Layer Two"
}]
}, "legendDiv");
legend.startup();