Importing imported photoshop but duplicating

Hi all. I'm having a strange behavior here and dunno if this is related with the latest Lightroom Classic updates. I have my catalog with a lot of photo and sometimes I find photos from my computer and just to check if they are imported on my catalago, I select the folder to import and if the phots are not highlighted, they are on my catalog. I always worked like this.

These days, I tried to do the same thing with some photos and Lightroom Classic shows all the photo as not part of my catalog, but I check on the photos folder and all are there and on the catalog too on lightroom.

Dunno why this is happening now, but there is a way to "validate" all the photos on the catalogo to avoid duplicated imported photos? Checked the metadata of the photos that are "duplicated" and are the same of the original imported on the catalog.

Thanks.