[perl #66818] Inconsistent behaviour when iterating over %*VM.kv

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# New Ticket Created by  Moritz Lenz 
# Please include the string:  [perl #66818]
# in the subject line of all future correspondence about this issue. 
# <URL: http://rt.perl.org/rt3/Ticket/Display.html?id=66818 >


The %*VM hash has the following structure

%*VM = (
    config => {
        '-Wcomment' => 1,
        '-Wall'     => 1,
        # many more items here
    }
);

as can easily be seen by %*VM.perl, and $*VM.keys has one item. However
iterating over $*VM.kv shows more than one key:

$ perl6 -e 'my $keys = 0; for %*VM.kv -> $k, $v { $keys++}; say $keys'
141

Somehow the inner hash is flattened. Using a normal hash I couldn't
reproduce
this behaviour.

Cheers,
Moritz