5 doman controllers have the same SID

Recently at my company we did a migration from NT –> AD 2003 Native at the
forest level. I am not experiencing replication issues. However, the problem
(or is this really a problem) is that all five of my domain controllers have
the same SID!

– what problem could this cause
– how is this possible anyway
– would this require rebuilding all servers

Can someone please explain to me why this is possible, because I am
wondering if I am experiencing issues that I am unaware. Please advise…