I tried to place a platform from my inventory in an area where it was green, then I left click and it shifts to be under me where it's red and fails to place. Except it also disappears from my inventory. Maybe two bugs here.
What's actually happening is the foundation (option 2) is being placed when you left click but the object is not replicating correctly to the client. I've confirmed this bug and will address on next release.
I tried to place a platform from my inventory in an area where it was green, then I left click and it shifts to be under me where it's red and fails to place. Except it also disappears from my inventory. Maybe two bugs here.
This was happening outdoors.