I feel that I should know the answer to this, but I haven't a clue. I note that the scope in the foreach and while blocks is being unwound on each iteration:

our $x = 1;
for (1, 0) {
  print "$x ";
  local $x = 2 if $_;
  print "$x ";
}
print "$x\n";
__END__
1 2 1 1 1
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I would suggest reporting it to the Perl project on github as an unexpected inconsistency and possible bug.