Hello, transparent objects are sorted before being rendered, so that the ones in the background are rendered first.
That’s what you are observing in the editor.
In the viewer we have an optimization that merges all geometries that share the same material for faster rendering. The problem here is that all the flowers end up being 1 geometry, that will end up being rendered in 1 draw. So we can’t sort them, so the order is basically random. that’s a common issue with blended transparency.
however in your case, there is a solution. Since your flowers are actually not transparent, but “semi” opaque you can use Mask transparency (you may need to adjust the slider value). There are several benefits to it. First it should fix your issue in the viewer, and second the flowers will now catch the shadows.
I hope that helps