In that case I would propose supporting the case where we’re copying text from other applications – like SSMS apparently copying a column is the same as copying lines w/CRLFs.
It’s certainly unexpected to have the first line repeating, maybe just stop after the first line if there’s no CRLF highlighted. If not paying attention it’s easy to miss that the values aren’t what you thought you pasted and move on – this happened to me hence the bug report ;)