So Jay, any chance you recently updated markdown and that broke this?
Everything was upgraded in this release. You guys are definitely right that the trailing space is causing the problem, but my testing shows that the bug only appears on the latest release of Node (8.1.2). Reverting back to the stable channel (6.11.0) has resolved the issue. It’s possibly a bug in the beta, but it could be an incompatibility between 8.1.2 and the form parsing module. I’ll test it again when version 8 achieves LTS. That’s what I get for playing with beta software in a production environment.
Thanks for everyone’s assistance in debugging. I doubt I would’ve identified the issue without your help.