Map Viewer Polygon Label centroid
In the old map viewer, your labels get created as a LabelLayer:
Within that object, each label is separately defined with their own x/y coordinates.
In the JS 4.x API, there does not appear to be a LabelLayer object, but there are instead LabelClass objects. Oddly, they both seem to have the same placement properties.
I'm a little out of my depth on some of this JS stuff. It's not totally clear to me what the JS 3.x viewer was doing under the hood to calculate the particular placement of the individual labels. I'd guess that the way the new viewer sort of loads features as "tiles" has something to do with it. Line labeling in the new viewer is kind of goofy for that reason, with line labels being repeated across the "tiles".
I am also having this issue. Highlighted is polygon number 7, green is number 4, however the 4 is clearly placed within the purple seven boundaries. This is not helpful and doesn't actually change when I zoom in.
The labels being placed for the centroid places them outside of the actual polygon and users will not understand this. They will assume labels are incorrect, or that a feature is something that it is not. For example, the below CF label needs to be in the shape that has red fill but no hash marks. I can't use the labels because there are a few of these that are making the map appear incorrect. This is a real bummer.
