It's a bug, yes. I'm wondering what's wrong with local() then, since your equivalent does work as you would expect local to act: 
$x = 'abc de';
$x =~ m/ /g;

print "1=",pos $x;
{
    $orig_value = \$x;
    *x = \$tmp_new_value;
    print " 2=".pos $x;
#    ....;
    *x = $orig_value;
}
print " 3=".pos $$orig_value;
print " 4=".pos $x;

[download]
output: 
1=4 2= 3=4 4=4

[download]
"What should it profit a man, if he should win a flame war, yet lose his cool?"

In reply to Re^3: search position is getting reset after 'local' by Joost
in thread search position is getting reset after 'local' by jesuashok

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