@Kumasasa: It does occur when you have docs or cats in the from the 1.7-world (I played last 1.7.5) and then switch to the new snapshot (e.g. 14w11b). This is reproduceable.
However it looks this bug is only related to classic Minecraft accounts.
If they are not migrated to a Mojang-Account, it seems you have it. Now I have migrated the account and it seems the issue is fixed after this. Can someone else confirm that migration to the Mojang account will solve the issue?
@Kumasasa: It does occur when you have docs or cats in the from the 1.7-world (I played last 1.7.5) and then switch to the new snapshot (e.g. 14w11b). This is reproduceable.
However it looks this bug is only related to classic Minecraft accounts.
If they are not migrated to a Mojang-Account, it seems you have it. Now I have migrated the account and it seems the issue is fixed after this. Can someone else confirm that migration to the Mojang account will solve the issue?