Googled around a bit. Found an article here that might explain it:
http://www.huffingtonpost.com/jon-ho...b_4611936.html
Seems some other producer from a unknown series may be filing suit against Discovery over that episode in particular. He's claiming they stole the whole concept for those myths from a show he put together by the same name. Can't say for sure but it would make sense for Discovery to pull th ep until after litigation, so to avoid possible further damages if ruled against.