Whenever loading the Adventure Time Mashup Pack the game just displays the standard default Minecraft textures for the environment, while all the menu and GUI textures are replaced by purple and black squares. I have seen Reddit posts reporting the same issue with other packs including the Skyrim, Halo and Norse Mythology packs:
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killerbeenl83
migrated
Thank you for your report!
However, this issue is a Duplicate of MCPE-34633.
If you have additional information, please add it to that report.
Please search before reporting, as it's likely that one exists already.
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