Providing details and examples might help diagnose the issue you are seeing.
As for your question: If you have an item, you believe is being detected incorrectly, you can use Lightroom Web to perform that import as it bypasses duplicate detection and will sync back to your Lightroom Ecosystem clients.
For a gut check, Lightroom Desktop looks at the following.
Capture Time match exactly
A duplicate is determined
If the internal hash matches an existing file's hash a duplicate is determined
If none of those things then it is not a duplicate - or it is a bug.
Can you provide an example of a file that will not import and its faux-duplicate? That would allow for testing and repeating and ultimately writting a bug.
My EOS R6 has a continuous file-naming system; there are no duplicates so if Lightroom detects a duplicate, it's per definition a bug. I'll try to circumvent this with the online environment for the time being; another band-aid fix. Like having to disable Gsync everytime you use an Adope app. Hundreds of complaints online and still no fix from Adobe.