The reason the HGR load cases are set to "not active" is because they don't represent the final piping system, and the results can be misleading if this fact isn't recognized.

As to your "abnormal huge restraint loads", to understand this do the following:

1) Copy the job to a new "test" job - say "Hgr_Test".
2) Bring up the piping input and change each hanger location to a full "Y" restraint.
3) Run a single load case with just "W".
4) The results for the restraint loads at the (former) hanger locations should match the (former) "not active" load case of the original job.

5) If the restraint loads don't match, then you have a non-linear job where the hanger design is iterating for convergence, most likely eliminating "+Y" restraints that lift off. You should be able to determine this in the original job where the restraint load at your "+Y" locations is reported as zero in the (former) "not active" load case.