I'm afraid that I'm not technical enough in these matters
But, I did read somewhere that the issue comes from the fact that the mixture is too lean in idle in order to make the bike Euro4 compliant, and then once you pull the throttle, the mixture becomes too rich too quickly.
Some people have been saying that a mapping change in the ECU would actually resolve the issue.
At the same time, the Z900 is also Euro4 compliant and it does not have this problem.
Perhaps the way the RS is built - more torque and HP in the lower rev range than the Z900, maybe that makes a difference.
Would be interesting to find out what's the real cause of this issue.