I don't know where you saw that at.
I did initially until I thought about it more.
Hmm...so I looked into it a little more. Maybe I read it wrong. This is what the patch notes said:
"Fixed an issue to prevent Force Fields from pushing units during construction."
I think I read it wrong. I thought they were saying that they fixed the force fields so that when you put them down they wouldn't push the units anymore. I know that I have seen a few forcefields that trapped the unit inside of it.
I checked the Unit Tester and I tried it against the AI and the FFs still push the units and so I can only think of one thing:
Also, "Workers gathering minerals can no longer continue to harvest minerals if they are pushed away by a Force Field."
FF around the Nexus/CC/Hatch and you take their income down to 0.
I really hope Blizzard doesn't do anything with the FFs.