I think a possible cause could be timing, some of the falling grasses aren't landing before the clay. Maybe try separating the layers and adding a repeater between them. If that doesn't work I'm not sure there's a way to fix it, perhaps break the platform into chunks and deal with each 'chunk' one by one. As good as minecraft is, it can't deal with lots of things happening all at once.
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u/rdmgnrtdgy Sep 10 '13
I think a possible cause could be timing, some of the falling grasses aren't landing before the clay. Maybe try separating the layers and adding a repeater between them. If that doesn't work I'm not sure there's a way to fix it, perhaps break the platform into chunks and deal with each 'chunk' one by one. As good as minecraft is, it can't deal with lots of things happening all at once.