To reproduce:
1. Create a world in 1.12.2
2. Place a pumpkin
3. Open the world in 17w50a and look at the pumpkin
MC-123143
Pumpkins placed in 1.12.2 turn into non-sheared pumpkins when upgrading
Resolved
Works As Intended
0
Only pumpkins placed on grass/dirt will have this behavior in an attempt to convert all the world-gen ones.