I've heard that HCM is being used to sort out the layoff list. If, for whatever reason/factor (i.e. age, benefits and total compensation are as good a guess as any), they would like to see you go, then it is just a matter of whether they think you will leave on your own or not. Being satisfied in your job and/or unlikely to leave tells them that they'll need to lay you off. Not being satisfied or thinking about leaving gives them hope that they won't have to pay out a severance package.
The sad truth is, @Ovt8Fj7-1mjf is right. If they want you gone, they'll find a reason for it, but you can delay it by making it seem like you might be on your way out on your own. Not for good, but still...