I had an issue with lots of repeated files and in order to fix it I wrote my own script to calculate a hash on all files and then check which are the same. This worked very well and with it I found that I have the same exact file imported into different folders...
In my setup all the files enter those folders through an import on Lightroom.
When I digged further I found out that:
1) the files have the same MD5 hash 2) they are exactly the same 3) they have the same EXIF data and it matches reality (CREATED DATE) 4) They have a different date on the filesystem 5) The file was imported to the date the file has on the filesystem
I am very surprised with this. When we move files around the file date changes but it seems that Lightroom is importing based on that and not on the METADATA inside the file.
Greetings, Updates for the Adobe Photography Products were released on 10.20.2020 that include fixes for these issues. Please install the most recent update and confirm that your issue is now fixed. Please let us know if you encounter any issues. Thank you for your patience.