I had the quirky, garbled screen at the point when the POW exchange was announced for the first time.
I did not see the message or any explanation of what the value of this is. There's not even a mouseover tooltip to explain the value when you authorize the exchange with a signature.
What exactly happens when you do the exchange?
The manual says the other side must agree to exchange 1/3 of the prisoners and there is a slight gain in VP and NM. But I see no news or info in any of my turns since offering the exchange. I assume this means it was rejected, but I don't know because nothing happens.