I have moved from all active scanning to all LSpush via logon script.
After I made the switch I noticed I could no longer change the "Set computers to non-active if not seen the last X days" The number of days would revert back after restarting the configuration console.
But if I enabled Acitve scanning I could then change the numbers of days and it would stick. Might be something you want to test and see if you can re-create this.
