For this to work with Data::Dumper you need to set $Data::Dumper::Useqq = 1; Otherwise the \r isn't replaced by visible chars.

perl -MData::Dumper -E "print Dumper qq<a\rb>"
b';R1 = 'a
[download]

perl -MData::Dumper -E "$Data::Dumper::Useqq = 1; print Dumper qq<a\rb
+>"
$VAR1 = "a\rb";
[download]

One of the main reasons to prefer Data::Dump over Data::Dumper for debugging :)

80 chars really sounds like a display limit though, rather than an invisible char