Wait... What?
My RSS feed doesn't respect LJ cuts? HFS! *facepalm* OMG, I'm SOOOOOOOO sorry you guys! I can't apologize enough! The original post had an LJ cut, and worked fine, but the RSS feed apparently needs the specific HTML, and I can't change ANYthing posted to the RSS feed. Like, even if I deleted the original post, now, it wouldn't matter. It's already posted to the RSS feed, which exists totally separately from my journal, and I can't TOUCH anything on that feed. There's just no way to get at it.