Affected world templates:

• Halloween Mash-up
• The Nightmare Before Christmas
• Redstone Mansion
• probably more

Steps to reproduce:

1. Ensure you own one of the affected worlds/mash-up packs
2. Go to the Create New World screen of the affected world template
3. Press "Read more" in the "You can't earn achievements." notice

Observed result:
There is no reason specified as to why achievements are disabled.

Expected result:
There is a reason specified as to why achievements are disabled (e. g. "This world's creator has decided to disable achievements for this world").

Original description:
I show with images as it does not let me get achievements even if I put it in survival mode in bedrock, the strange thing about this is that it does not give any explanation of why it does not let me enable achievements in this mash up pack, while in the minecraft console edition version if I let me as long as I play in survival.
All this happens in the mash up pack Halloween and The Nightmare Before Christmas, I think it also happens with other mash up pack but so far I only know about these two.