how can I avoid this?
it is a too stupid question? :D
Your texture looks weird because of it’s topology … look at the mesh and how it’s constructed. It’s been a while that I tried mapping some texture onto a sphere but as far as I remember your best bet would be to use a 3D program like cinema and export the sphere as xfile with the proper texture coordinates.
This might be related to your question https://discourse.vvvv.org/t/7716?!
Hope that helps.