I have one student who is trying to receive photos in Google Photos on her school account from her coach. The coach does not have any issues sharing photos with anyone except this one student. The coach tries to share and it says:

When I open Google Photos as the student, I click the Sharing section and I see this:

My first thought was Family Link, but upon asking the student and family, they do not use Family Link. (of course, unless they set it up years ago and forgot about it or something... But I don't have a way to verify that it's not actually set up, I don't think...)
Then I thought maybe it was something with the Under 18 setting. However, the coach has successfully shared the photos with all other students without issue.
Any thoughts about what might be causing this for one student?