Working on my project, after months of work, this bug appeared and I don’t know what could have caused it. The various painted Landscape GrassTypes started to appear with a considerable delay and this happens both in the editor and in the build. But if “Landascape Editing Mode” is activated in the editor, the layers will appear instantly. Here the link to a descriptive video:
for the moment I have gone back to the last working version but it would be very useful to understand what happened, also in the past I had already seen this bug on 4.16.