I caught a Smeargle today following a photo bomb with my Lock-On / Focus Blast Registeel. The Smeargle I caught, to my surprise, knew Astonish / Focus Blast, not Lock-On.
Why did Smeargle not Sketch Lock-On, and can this happen to any other moves - in other words, why does Smeargle not Sketch a move? My assumption at the moment is that it cannot learn moves introduced to Pokemon Go after Sketch such as Lock-On, and Transform. However, I couldn't find any information online to support or deny this, and I am somewhat surprised that Niantic didn't make moves introduced after Sketch like Lock-On learnable. It could be a bug.