My Festive Mash-up 2016 pack doesn't start-up. Every time I try and play it(by creating new world) it says "There was a problem loading this world", every time I play an existing world, The texture pack is gone and it's normal Minecraft. It has been happening shortly after 1.14, the village update was released.
Thank you for your report!
We're actually already tracking this issue at MCPE-61368, so I will resolve and link this ticket as a duplicate.
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