From @smls

Calling .clone on an Array returns a new Array object, but (even
shallow) changes to one affect the other​:

  my $a = [2, 4, 6];
  my $b = @​a.clone;
  say $a.WHICH; # Array|68924240
  say $b.WHICH; # Array|68924304
  @​a.push(8);
  dd $a; # Array $a = $[2, 4, 6, 8]
  dd $b; # Array $b = $[2, 4, 6, 8]

IRC comments​:

  <jnthn> An Array is an object, with a bunch of attributes, once of
which is the actual storage.
  <jnthn> I'm guessing Array doesn't have a method clone of its own,
so it does The Default Thing in Mu
  <jnthn> Which keeps the storage
  <jnthn> It should probably get its own method clone
  <jnthn> I thought that had already happened. :
  <jnthn> :S
  <jnthn> But yeah, it wants fixing. The current behavior is crap.
  <timotimo> cue writing spec tests for .clone of pretty much every
single class :)

From @zoffixznet

Thank you for the report. This is now fixed​:

Rakudo fix​:
rakudo/rakudo@dc69dafc42
rakudo/rakudo@11d005e605
rakudo/rakudo@4b85db6e8c

Tests​:
Raku/roast@a460cdc7ac
Raku/roast@ea5cc0d8c2

The RT System itself - Status changed from 'new' to 'open'

@zoffixznet - Status changed from 'open' to 'resolved'