Solved it. There was corruption in the buddypress tables caused by them not having a primary key that was autoincremented. When the new users were imported all their buddypress specific metadata was created with an id of zero. I could have restored from backup before the corruption, but decided to delete the zero id table rows instead. The loss of the key and autoincrement was something that happened when I converted some data to harmonize a live site with a development site and didn’t realize the key and autoincrement would be lost.
