Doubt about tiny prims

Hi all, well i've got a little problem here with the tiny prims, everytime i do a tiny prim, i used to do them with the spheres, when i try to move the prim it dissapears for a moment and then appears again, it only happens when i made a tiny tiny prim, so my question is, is this normal or it's part of my optimization configuration of sl?. Thanks for anticipate.