I was adding the collected issues to 'Walled In' https://www.comicogs.com/comic/92455-walled-in and, as it happens, the last issue is also called 'Walled In'. I selected 'Create Walled In' but each time a link back to the collection was saved. I fixed this by changing the issue name to 'Suicide Squad #30' and then renaming the issue to 'Walled In' on the individual issue entry page.
Thanks for the heads up DrBoots. We will look into it.