Copy method seems to ignore duplicatesStrategy

I had another look at this. I’m still a bit confused about what is considered duplicates and what is not. For example

copy {
  from [f, f]
  duplicatesStrategy = DuplicatesStrategy.FAIL
  into target
}

reports a duplicate path whereas

copy {
  from f
  from f
  duplicatesStrategy = DuplicatesStrategy.FAIL
  into target
}

does not.