Thanks to David at InDesign Secrets I’ve verified a little bug with InDesign’s Split Columns feature. Apparently if you try to split columns at the end of a story it just won’t work.
The solution is easy enough though:
- Add an extra empty paragraph to the end of the story.
- Split the column as you would normally.
- Delete the extra empty paragraph.
I can’t explain why it is that you need the extra paragraph there to make the column split, or why you can delete it immediately afterwards with no ill effect, but I am certain this method (while slightly cumbersome) works.