Loads of folk do describe this as being orange and green. I can't see it myself - it is a dull orangey red, but it's still red, and it might be a turquoisey-blue - but it's still blue to me.
Mdina never had a green melt in a pot, early on. (They might have, a lot later, I don't know) It does say green glass was used in Mark's book, but that is an error, which most likely arose because Malta Decorative glass items in (true) green were confused with being Mdina at the time.
There is a lovely green shade that can appear - it is the result of silver chloride creating a clear amber swathe during the making, which lies over the teal-blue base, giving rise to green.