Huh, the problem I mentioned last time might only be occuring in the new fiction submission area. Which would make sense, that's an area that is more likely to be infrequently user-tested by frequent users. So easy to miss a small error like that.  It won't let you schedule without meeting the minimum requirements

If you discover this tale on Amazon, be aware that it has been unlawfully taken from Royal Road. Please report it.

Also, it doesn't specify minimum posting requirements for chapters until you attempt to publish/schedule.  While 500 words is a low bar to hit, it still should be mentioned.  You already have one for the chapter title.