DBD::Sybase: syb_server_version_string truncated?

As I understand it, syb_server_version_string should return the full 
@@version string. However, it seems to be truncated after 15 characters:


print "$dbh->{syb_server_version}\n$dbh->{syb_server_version_string}\n";

12.5.4
Adaptive Server


Am I doing something wrong? The connection is OK and subsequent queries 
run fine.

Thanks in advance,

Rob V.