Painting Prefabs on planets *help*

I have been tinkering and trying to design spherical planets using polybrush and following the design from this unity tutorial- Make a Planet in Unity 2019 with Polybrush! (Tutorial) - YouTube - but am having trouble painting prefabs on my planet as when I do the lower on the planet I go the prefabs start to float far away from the planet at an alarming rate. Anyone know whats going on or any workarounds?