At some point LR Import started defaulting to the DCIM folder on the SD card under files instead of the card as a whole under devices. This can create a major issue, especially if you don't know better and aren't paying attention. Sony for example doesn't put their video files in the DCIM folder, so even if 'include subfolders' is on, it would be easy to format a card without realizing that you never imported everything. The simple solution is to go back to selecting the device and including subfolders. Not sure why it changed.