BBID conversion problems

We are converting students to BBID. We are not using an SSO at this time. We have tested this out with some students. I connect them to BBID. (They are sitting right next to me and I'm watching them go through this process.) They log in for the first time and they receive the conversion message, then some of our students immediately receive an error that they authenticate with google and must sign in that way. It is not a choice. We do not want our kids to authenticate by using “sign in with google”. We want them to have a BBID. The only way around this is to have them sign in to google, then go to blackbaud.com and log in to their profile, then disable authentication. It's crazy! They have never authenticated with google. Why do some (not all) of our students have to turn off something they never turned on? We are talking with support they seem stumped. I'm hoping someone here has some intel that will help us identify why this is happening to some (not all) of our students.