Items appearing as magenta boxes and advancement checks seemingly not working for images as intended. Medals are used to symbolise completion based on advancements, yet show anyway despite conditions not being met.

https://hastebin.com/kucevegawe.xml

Strange... When I get back i'll take a look at it.

Yeah, the item stack was my bad, the meta was incorrect.
However the advancements don't work, unless I made another silly mistake.