In 1.8 Resource Summaries have suddenly become required fields. For sites with thousands of faculty, this is a huge training problem, and makes creating courses take much more time for faculty*.
This looks like a bug caused by implementing the new forms API, as it is not mentioned in the release notes as a new 'feature' in 1.8.
*If you do a good job of writing a summary, it can take a good deal of time, and faculty like to do a good job on their courses. Plus many feel that good summaries will act like "Cliff notes" the students will read the summaries and not read the full articles.
There should be a way to turn this off in the Admin module config along with all the other settings that can be set for resources, so that sites that have large numbers of users and who don't want to force all of them to summarize their documents can easily disable it (without having to hack code).
Or even nicer, a capability:forceyoutosummarize, so that a single site could have some courses where summaries are forced and others where they are not.