Unable to invite family member to shared password group in iOS 18 password manager

I have created two groups in the new password manager: one to share with my son and one to share with my daughter. Both of their phones are running iOS 18. I had no issues sharing a folder with my son, but when I try to share with my daughter, her phone number and email address are grey and when I select her, I get a pop-up box saying that she "does not have a device that can join the group" and then references the fact that she needs to have iOS 17 or higher, which I know she does. I don't know why she is not recognized as having the latest iOS.

This may or may not be related, but my son's location is listed below his name in the header in Messenger while my daughter's isn't. Both of them share their location with me and I can see both of them in the Find My app.

Any suggestions appreciated.

Thank you!