There's an upcoming Pokemon series episode that's going to skip its scheduled slot in the west on Disney XD. It'll mark the first time the Pokemon anime hasn't been able to air an episode since back in 2002, interestingly enough. Why? Disney XD is likely hoping to get ahead of any potential outrage or vitriolic viewers by avoiding showing Episode 64, called "Touchdown of Friendship."
The particular episode finds Ash making friends with a group of Pokemon called Passimian. Passimian are monkey-like creatures that he tries to imitate by dressing up and acting like them, which mirrors the behaviors of apes in the wild. Unfortunately, he also paints his face black to resemble the Passimian even further. While it's an innocuous act that Ash is taking part in, it could easily be misconstrued as an act of blackface, especially judging by the shot below.
Of course, The Pokemon Company hasn't come out and stated directly that the episode is being locked away and never shown to viewers. It's possible it's just not going to be airing in the normal order it would be seen in, or it could be planned for another time. Most likely, however, the case is that everyone wants to avoid any kind of controversy that could come along with airing Ash's actions. It's easy to understand why.