Yeah they probably accidentally had someone with the Copy status and didn't realize it. The actual Lilina would be sad to hear that her friends didn't even notice they were travelling around with someone who THINKS they're her. Or maybe she would get turned on by it. I dunno.This actually makes me wonder if the "Princess Lilina" in your party was actually someone else under the Copy status.
And that makes me wonder if it's plausible for other characters to be keen-eyed enough to tell the difference, especially the ones that don't know Lilina that well.
Then again, her sister and their chancellor do know her well enough for this, and Kepiat probably has a keen enough eye for detail that she wouldn't be fooled by a fake either. Hm.