Duplicate must be the cursed function of CF. Recently I posted about a hotfix that was put out to correct issues with Duplicate. Rob Brooks-Bilson noted that there still seems to be issues:

Unfortunatley, it looks like this hot fix STILL doesn't fix all duplicate issues. I'm running into a problem while porting a (badly) written CF 4.5 application where a structure of arrays that is being manipulated by reference then passed to a COM method is causing an error. If I serialize then immediately deserialize the struct of arrays before passing it to the COM object, all is well. Using duplicate, however, results in a COM automation error in CFMX.

I haven't been able to test this yet, but it looks like the function may still need tweaking.