This has been an issue since at least 10.2.0.3, and appears to still be the case in 11.2.0.3, almost five years later.
A TIMESTAMP datatype in GV$SQL_BIND_CAPTURE is not printed. Fortunately, the following works.
select anydata.accesstimestamp(value_anydata) from v$sql_bind_capture where sql_id='&your_sql_id';