Transform Item Event Crashes The Game

When creating an item event that transforms the item to another item, the game crashes.

Steps To Reproduce:

1. Download, install and start a new world with the supplied pack (experimental features on)
2. Find the 'apple' item in the equipment tab (or give yourself the grunt:transform_event item using the give command)
3. Use the item and the game will crash

Expected Behavior:

• Transforming items in an items behavior file does so correctly without crashing

Actual Behavior:

• The game crashes when transforming items