LrC creates a separate subfolder with the "same" name, just different case

i have a folder with a subfolder named MLS. when i exported images to it, i mistakenly entered “mls” (i.e. lower case. LrC dutifully created a subfolder labelled mls, and it now shows two subfolders: MLS and mls. i tried to move the image from the latter to the former but LrC wouldn’t do it

Windows File Explorer only shows one subfolder: MLS, with all the images