It seems that the time you had imported the images in Lightroom from your Camera Card, you had selected the " Add " option in the import window.
I would request you to please remove that folder from Lightroom and then reimport the folder from Card using the " Copy" option.
Please let us know if it helps.
It seems like when you imported the images from the card you added them into the catalog instead of doing a copy. in the import window right at the top we have option to "copy as dng", "copy", "move", "add"
choose copy then on the right we will get the destination panel; in which we can select the destination in which we have to copy the images from the card.