Jeppe Vennekilde

It's annoying because all they have to do, is just make the animation use a time that starts with the client.
It couldn't matter less if the beam animation is not synchronized for everyone which i highly doubt it would be anyway

I have found the cause of the problem
if you change the NBT tag Time and DayTime in the level.dat file to 0 (both have to be changed), it will fix the problem, and if you change it to a very high number it will cause the problem (i used 989210110 because it is from another world with the issue)

So the issue isn't connected to minecraft 1.0, but to the age of the world. If you can't wait for mojang to fix the issue, all you have to do is use NBTExplorer, open the world with it and change Time and DayTime to 0