Get used to it...in fact, you should be used to it by now. Not only CAN they do it, it's exactly what they try to do when they make changes.
Remember the training bug? The one they denied existed for a long time? Once they actually figured out what was happening, they changed it. People signed players to contracts expecting the training bug to stay and ******* when it didn't. Sooner or later they'll fix SBs and people will ***** about how unfair that is too.
You can either adapt or get behind. Either way, ******** about it isn't going to get them to reverse it. They may tweak it some more in the future if they aren't happy with the results, but it's here to stay.