My nephew has minecraft for the nintendo switch (cartridge). He tried to load the adventure time mash up pack template and the treehouse was there but it was all made up of the original/normal minecraft textures and the monsters and animals were all original minecraft version as was the music. He said he clicked something so he thinks it’s a setting issue but I can’t find any setting that says make mash up packs appear like normal minecraft nor do I understand why that would be an option. Please help.

Also I totally guessed at affect/version. I am not that minecraft savvy.