Add Students isn't previewing a list if a group code was used

When you add students to a class notebook using a group code such as Subject-9ENG, you used to get a preview of the names in that group in the 'did we get it right?' window.

Tried to do it just now and the preview isn't there anymore. This is a pain for teachers of core subjects like English, when there are 8 groups 9 ENG to choose from.

Is this the result of an update, or a bug at my end?