P: Import is creating OS - level duplicate files named (-2) when using Devices rather than Files

Hi! Same problem over here!!

Windows 10...I wonder if it has to do with windows not being able to read .CR2 data. (I just switched over to a Canon 6d mark ii from a nikon d3300). I noticed that in addition to thumbnails not being displayed for cr2 files, in windows explorer|file properties|details  all the camera fields are blank...so 'date taken' etc are all blank. But I would assume that wouldn't affect lightrooms ability to read and compare that data, which I assume exists in the raw file even though windows doesn't display it...

Btw, I think I figured out why the Nikon files imported again...I used to convert to .dng, but now with the new Canon I am just copying the raw files, so when I imported this morning it makes sense that it made new copies of the photos since they were NEF and not DNG. HOWEVER...the import was only partial, and I did a couple of imports of my Nikon card, and each time it only imported a subset of all the files that could be imported. So why is that? Why wouldn't it import all the files on the card again, instead of spreading out over 2 different imports? That is really weird. Anyways, so it is apparently just the Canon .CR2 files that are getting duplicated with the filename being appended with a '-2'.

Also, thanks for all your responses, I will do some more digging here as well...

OS?
Is the drive formatted as Case-sensitive?
Screenshots of the Folder/Import Dialog?

He said that he is getting -2 added to the file name so we know that is matching.

Windows only comment: on Windows there are 2 sizes for a file. 1) actual size; 2) size on disk. Moving the file won't change the actual size but the size on disk is affected by both the disk technology (SSD vs HD...) and how it was formatted.

Perhaps Lightroom is checking the latter size?

The exact criteria for Classic is  File Size/Filename/Capture Date. If all three match it is a duplicate. If they do not it is not treated thusly. If you rename when importing this will make the duplicate check fail on Filename.

I'm probably out of date as I no longer use this feature but a suspected duplicate had to match the capture date and file name exactly. Not sure how it happens but copying files between folders can sometimes change the capture date. Because the file name is identical, a suffix must be added as 2 files with the same name cannot exist in the same folder. But something else is enough different that it does not treat them as the same image.

These are new photos and some older ones (maybe a few weeks). It seems to just randomly import images that have already been imported....and the thing is I know it is recognizing the duplicates because it renames the files with a '-2' on the end of the filename.

Are these newly captured photos? Or ones that have been on the card for a long time?