Please follow the advice given in SO:how-can-i-dump-a-string-in-perl-to-see-if-there-are-any-character-differences and dump both strings either with

 perl -MDevel::Peek -e 'Dump "ABC"'

or

use Data::Dumper;
local $Data::Dumper::Useqq = 1;
print(Dumper("ABC"));
[download]

to see what's happening.

We can't tell how your data-sources encoded your strings and you haven't even used code-tags to help us at least a bit.

Update

changed tiitle to make a difference