Did you ever have a chance to look into the weird Data Link Escape character showing up in post Markdown and HTML? See https://gitlab.com/jeremy-w/macchiato/issues/55 for example and diagnosis.

My conclusion was "Issue is the \u0010 AKA ASCII 0x10 AKA "Data Link Escape" character Ctrl-P. Pretty sure that's supposed to be an LF AKA ASCII 0x0A."