Problem/Bug WorldEdit /br sphere

So, I've been using /br sphere sand 5 to do some brush commands for my spawn. They were working just fine a few days ago. Now that I am trying it again, this happens:

Please note: Don't judge the spawn, had to change things to diamond to make sure //replace wouldnt remove the Oak Wood! lol

 

Try turning on WorldEdit's fast mode before making your sphere: //fast

 

That didn't work...

 

It's obviously happening because sand falls. Try placing some other type of block, then replacing those with sand. Maybe with //fast mode.

If that doesn't work, place the regular blocks, put barrier blocks under those blocks, then replace the regular blocks with sand.

If that doesn't work, I'm out of ideas.

 

Yeah, wanting to do the sand so it will fall and I can make a mountain easily... ended up using your idea before you told me and just took an extra 15 min! Thanks for the help.