I assume it is still legal for a list MP to vote independently if they want to they will get kicked out of parliament afterward. A government could still lose a vote based on a list MP?
Presumably if a list MP makes any noises about that beforehand or in some cases raises the slightest suspicion of representing voters interests their party may choose to kick that mp out of parliament as a precaution. Lack of discussion will take a lot of politics out of the public and it will be less democratic.
List MPs are the elected representatives of list voters that's how the system works. If you don't think they are reliable don't vote for those people to represent you. This is a bad law and not good for diversity in a democracy.