When I try to create a world using the Halo or Skyrim Mash Up Packs I get an “There was a problem loading this world” message. Also, if I try to load using either mash up pack in the active resources packs I get a glitched out world.
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However, this issue has been closed as a Duplicate of MCPE-34633.
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I’m having the same exact issue, any weird texture is default to a magenta and black checkerboard pattern