Why can I not liberate Austria or Czechoslovakia?

[ep1c_fail]

Below is a screenshot of a peace deal with Germany and Italy. I am the United Kingdom. I have the highest score and am going first.

Why can I not liberate Czechoslovakia and/or Austria? My allies are able to do this on their turn, but I cannot. For some reason it lets me liberate Lithuania, Albania and Ethiopia though.

 

[Ironside121]

How do you know that your allies are able to do it? Is this an MP session?

 

[ep1c_fail]

It isn't an MP session.

I know my allies are able to do it because I've run the peace deal through a number of times. On every occassion, Belgium has liberated Czechoslovakia. Though even if they had not, there is still no explanation as to why I can't.