The minecraft:grass item does not get upgraded to minecraft:short_grass and disappears instead. The block version does get upgraded correctly. On top of that, the statistics for the minecraft:grass item also don't get upgraded.

Steps to reproduce:

• Create a world before 1.20.3 Pre-Release 1
• Give yourself a minecraft:grass item
• Close the game and start 1.20.3 Pre-Release 1
• Open the world
• Notice how the item disappeared