I've reported this before and after catching a second mew ran into the same problem On the Pixelmon 1.10 server when I use the cloning machine to clone Mew and get a ditto in the tank, I retrieve the ditto and enter battle the but the ditto doesn't appear on screen at all. When battle starts a ditto health bar appears but the ditto does not, the invisible ditto is invulnerable to attack and when I throw a pokeball the battle immediately cancels. Switching pokemon also cancels battle. Sometimes the doesn't immediately cancel on the dittos turn with it saying its using transform but before it says it transformed into my current pokemon like in single player the battle just cancels. It doesn't seem to matter whether the cloning machine is on claimed land or not, as I had moved my machine into a large clearing I had made in the Jungle Hills biome which wasn't claimed and I still encountered the bug. With the second mew before I had even attempted to clone it I had uninstalled the client and reinstalled it to make sure it wasn't a client side issue but it didn't seem to make a difference, the bug appears server side. I'm not looking to be reimbursed, I know that once something is gone its gone. All I ask is that staff look into this when they got a chance. Thank you.
Akiros, Since the opening of PX2 on Feb 19th, I've personally tested this issue with three different Mews and have not run into this issue. This issue appears to have been resolved. If you have any further issues with Mew cloning on the new server: feel free to post a new thread, or send me mail in-game, I am quite active on the new node.