@Edent I would guess that one hasn't been set, or it has been set to a space.
WordPress can auto-generate excerpts by just grabbing the first 50ish words of the post, but I have a vague memory of some themes having an issue with that and not working.
@Wifiwits Forcibly switching people who are struggling, to a method of payment that is more of a pain and more expensive, is simply shocking.
Me!