Difference between uploading dSYMs zip file Or .dsym(s) folder Firebase Crashlytics iOS

Question

I am trying to understand the behaviour of upload-symbols tool. We can pass dSYMs as:

1. zip file
2. folder that contains dSYM file(s)
3. single .dsym file

First Method: When I try first method (zip file), some time firebase detects the symbols and sometime it does not, even terminal says uploaded successfully. I even wait for 1-2 days but still firebase keep saying missing symbols (tried uploading multiple times with this method). If I check the missing dsym id from firebase into zip file, I can see and it's there.

../Pods/FirebaseCrashlytics/upload-symbols -gsp ../Test/Resources/GoogleService-Info.plist -p ios ../Test.app.dSYM.zip

Method second and third: This method always works for me and firebase detects the symbols with few minutes. Now what I do is extract the zipped file then run upload symbols command.

../Pods/FirebaseCrashlytics/upload-symbols -gsp ../Test/Resources/GoogleService-Info.plist -p ios ../Test\ dSYMs

I was wondering why?