Some *able info, if anyone is interested:
Output on all releases:
https://gist.github.com/a68b094519839b939f8c70d66a80d8c0
Some possibly relevant commits:
https://github.com/rakudo/rakudo/commit/92bd7e4f54a92fa660f99b4d056d33a08fb98bd2
https://github.com/rakudo/rakudo/commit/6dae179a8418bd2fcf5cc
# New Ticket Created by Curt Tilmes
# Please include the string: [perl #132487]
# in the subject line of all future correspondence about this issue.
# https://rt.perl.org/Ticket/Display.html?id=132487 >
% perl6 -e 'my $proc = run "cat", :in, :out; $proc.in.say: "test\n"; say
$proc.out.get; $p