The code you've posted is incomplete and does not run. Thus; for anyone to help you, they must first make the snippet run. That's lazy & rude.

Second, your annotations are wrong. You claim this line "works fine":

$hash{$a} = threads::shared::shared_clone(@array); ## This part works 
+fine
[download]

But in truth it produces the error: Usage: shared_clone(REF) at ...

So, if you want some help; first make your code compile clean under strict & warnings; and then make sure that it does what you say it does. Then come back.