Custom Items and blocks randomly disappearing

Everytime I load up an old or new world with the pack enabled, some custom items and blocks disappear, the stuff disappearing is different everytime and I have no idea what's going on

Attached are screenshots of what should appear and the in game screenshot is what actually appeared…

 

The pack is More to Explore addon

https://1d10t1cstud10s.wordpress.com/more-to-explore/

Forcing the game to recognise the items through loot tables will give you the following content log error:

item redstone:(item name) is not valid

 

To replicate:
1. Enable the pack in game
2. Take note of the items that are in the creative inventory
3. Reload the game and enter a new world with the pack
4. Find that the missing stuff differs every time