This is a hardware malfunction. Somewhere in the transfer from camera card to Lightroom, a piece of hardware is causing this corruption. It could be anywhere in the chain ... camera card, card reader or USB cable/USB port, hard disk or memory.
you need to try doing the transfer with other hardware and if possible with another computer to try to isolate the bad component.
It appeared fine till I went to start editing it. Could it be Lightroom?
It's the hardware. Lightroom is only displaying the information given to it by the hard disk and memory; that information given to Lightroom is corrupted.
It appeared fine till I went to start editing it.
Yes, that's what happens sometimes with corrupted photos, the JPG preview that is embedded in the RAW is fine, and Lightroom shows you a preview based upon that preview which looks fine, but the RAW is still corrupted and that's what you see when you start editing it.