Copy and Paste Text Frames Duplicates Content

My designer is working on a magazine for us and was specifically adding photo credits into their own individual text frames. He created the caption for one image and added it to the inCopy assignment (the icml file and name of the content under the Assignment is #139). He then copied that frame and pasted it next to another image, just changing the text inside. 

The problem is, when that new text frame was pasted and then added to the assignment, it had the exact same name as the content that was copied—139 (photo attached). And an additional icml file wasn't created. For some reason, they're both tied to the same icml file, which means when I fixed a typo in one of those captions, the other caption immediately became the same exact thing. 

Is this a bug or is this by design? Should he not be coping and pasting text boxes like that?

The fix, as far as I found, was to choose one of those two text boxes, Unlink Content, then re-add it to the assignment. When I did that, it does change the file name to something different, so this doesn't happen. Is there a better way to do that?