War Diplomacy glitch or human error?

I was playing a Local Network with my friends. On two different occasions i was at war with one of them and they offered me a deal. I modified the deal then sent it back to them. Then the deal i offered was sent back to me to accept or decline and I accepted it. They both got mad when it happened. I am curious if this is a glitch or what happened that i could accept the deal i modified and sent to them?

Bug (and an abusive exploit when used by someone on purpose): http://forums.civfanatics.com/showthread.php?t=516718

Wow O_o

Hope firaxis will fix that bug.

thanks all. yes that is really messed up. and considering the thread Browd showed me was back in january...they really need to fix that asap.