Note that the values are not copied, which means modifying them will modify the contents of the hash:

for (values %hash) { s/foo/bar/g }   # modifies %hash values

Can you give an example on what you are seeing?

SK

Update: Are you not seeing this behavior?

#!/usr/bin/perl -w

my @array = qw(1 hello 2 hello 3 hellome 4 hellothere);
my %hash = @array;

foreach( values %hash ) { s/hello/hi/g; }

print +("$_ = $hash{$_}\n") for (sort keys %hash);
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Output

1 = hi
2 = hi
3 = hime
4 = hithere
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