I have been failing jobs for this under 110-3. The job has to be installed as per the manufactures instructions. Most manufactures only allow 1 neutral wire per terminal. I am glad that it is finally written under another code section that can be written up for. I once looked inside an old service panel and wondered who left a small red light on inside this panel. Imagine my surprise when I found out that the red light was really a neutral conductor glowing red hot. It was doubled up under a screw terminal and they were both very loose.
The UL product standard for panelboards has not permitted more than one neutral under a single screw for a long time. It does still permit in some cases more than one EGC under the same screw, but not neutrals. The rule has been enforceable under 110-3(B) but was added in Article 408 to make it very clear and to make sure that more installers are aware of the requirement.
Panels that are in compliance with the UL product standard for Panelboards are required to have one neutral termination space for each breaker space. They are not required to have an EGC terminal bar and most of the time, in a new panel, where neutrals are doubled up, it is because the contractor used the neutral bar for EGCs. This in itself is not a violation at the service panel, but it becomes a violation when you double up a neutral.