If I join v$rollstat to v$transaction and find that a rollback segment has active transactions but n

Using 9.2.0.7
If I join v$rollstat to v$transaction and find that a rollback segment has active transactions but no corresponding entry can be found in v$transaction, does that imply that the system is rolling back something?

am using the following query to view rollback information:

select
  rs.usn "Rollback Number",
  s.sid,
  s.username,
  t.start_time "TX Start Time",
  t.used_ublk  "Undo blocks",
  t.used_urec  "Undo recs",
  rs.xacts,
  rs.extents
from
  v$session s,
  v$transaction t,
  v$rollname r,
  v$rollstat rs
where rs.usn = r.usn and
  rs.xacts != 0 and
  rs.usn = t.xidusn (+) and