[perl #127190] Perl 6 has 0 elements ( .hyper.grep )

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# New Ticket Created by  Alex Jakimenko 
# Please include the string:  [perl #127190]
# in the subject line of all future correspondence about this issue. 
# <URL: https://rt.perl.org/Ticket/Display.html?id=127190 >


Regular grep:

<AlexDaniel> m: say ^10 .grep: *.is-prime
<camelia> rakudo-moar fec061: OUTPUT«(2 3 5 7)␤»

With hyper:

<AlexDaniel> m: say ^10 .hyper.grep: *.is-prime
<camelia> rakudo-moar fec061: OUTPUT«   it has 0 elements.␤()␤»

With race:

<AlexDaniel> m: say ^10 .race.grep: *.is-prime
<camelia> rakudo-moar fec061: OUTPUT«   it has 0 elements.␤()␤»


More:

<AlexDaniel> m: my @a = ^1000 .hyper.grep(* > 5); say @a
<camelia> rakudo-moar fec061: OUTPUT«   it has 0 elements.␤   it has 0
                    elements.␤   it has 0 elements.␤   it has 0
elements.␤   it has 0
                    elements.␤   it has 0 elements.␤   it has 0
elements.␤   it has 0
                    elements.␤   it has 0 elements.␤   it has 0
elements.␤   it has 0
                    elem…»

What is this “it has 0 elements.” thing? Why do I see it? Why it returns an
empty list?