Not retaining target

Dear forum,

This is my first post on here. I am developing products with playcanvas and I have forked the placed rocked model PlayCanvas 3D HTML5 Game Engine . I have noticed some bugs that I hope have been resolved. When placing the model on a surface, it will mark it there but then upon moving the mobile device it will follow the device at times and also scale the model if you turn and come back to it. I was hoping to create an immersive environment which really needs stability of placement. Any pointers would be super helpful.