Google App Script not updating after saving changes and publishing

The "latest code" URL is a developers-only address, with a unique ID followed by /dev. Only the owner of the script can access this, and it will always show the results of the current code.

The published application has a URL with a different unique ID followed by /exec. To show results of updated code, the author must first save a new version, then publish that version.

That is not the problem. There appears to be a bug which does not update the published script. I needed to delete the script completely, save it and add back my saved code. I kept publishing, getting the "exec" version and it never used the new code until I did this.