This would be due to not using correct form fields. The records list is hard-coded to use the default fields "firstname" and "lastname" for the name column and the default "email" field for that column. In the current version, it's not possible to set this the wrong way, but you could have set them otherwise in an older version and already had it saved that way when upgrading.
Each of these three fields must be used for both individual and group registrations. For group registrations, they must be set to either "Billing Info" or "Members & Billing".
Check and re-save the default settings for these fields in the setup of each field. Then check your events. Open and re-save each event... making sure that they are set to use those three fields as default... OR that you set it appropriately if not default.
Once it is set correctly, you'll see that you won't be able to put it back to the an incorrect selection.
If you were using fields you created in place of the default ones, that data will NOT show for name and email in the records listing. This is the problem though. Just setup, not a bug or anything goofy