[Creative 1] Block Changing

My Username:
TheGamingBuds125

Server Bug Was On:
Creative 1.

Description:
I was building in a Desert biome and next to grass. I was placing smooth sandstone on the dirt and next to the grass-- sometimes in the middle-- and it just randomly turns into grass!

If you know how to solve this problem, TELL ME!

And also, if your confuzzled of all this.
The smooth sandstone just turns into grass.

 

The sandstone turns to grass, or the dirt does? If the dirt is changing, thats normal. If the sandstone is changing, that's just weird.