In the timing report, paths that are already constrained by an OFFSET constraint are appearing in the unconstrained path report. Are these paths actually constrained?
Yes -- if the paths are also listed under the OFFSET constraint, the path is correctly constrained. You may safely ignore the path in the unconstrained path report.
This problem is fixed in the latest 5.1i Service Pack, available at:
The first service pack containing the fix is 5.1i Service Pack 1.