So 2 of the 3 sites have been fixed up by getting them to place the handset back in the cradle whenever they place a call on hold.
3rd site is different, where they get a call transferred to them and it automatically just goes to speaker, without placing the call on hold or anything - this sounds a lot like the other issue. Customer has figured out a way to get it off speaker, so i guess i will have to wait and see what samsung come up with.