Is Terrain:FillCylinder() are snapped to voxels, and will fill them only on grid?

Hello guys. I’m making my plugin for manipulating terrain. I rescripted every shape that I use for brush: wedge, ball, cylinder, block. And when I tried to see diffirence between default roblox Terrain:FillCylinder() and my function, I got some… strange results:
image
Left is my plugin, Right is Terrain:FillCylinder(), orange is dot where I activated brush.

Looking on right cylinder, I can see that Terrain:FillCylinder is always snapped to grid, while my cylinder not (because size was 16 studs = 4 voxels, my not snapped to grid).

Is this occuring only for me, or not?