unarchive remote_src not working, no effect

[Spike Robinson]

the copy option in the unarchive module is deprecated and we are advised to use remote_src instead

However, in an otherwise identical script, having staged the source file to the target machine successfully in a previous play,  if I use copy = no the play succeeds, but if instead of that I use remote_src = yes or remote_src = no, the play fails, in both cases saying the file source does not exist. 

So in summary remote_src either has no effect or perhaps expects some of the other parameters to unarchive to be different than what the copy option expects them to be.