I hit the same issue yesterday. It appears to be a left separator/delimiter in a font (or browser) that doesn’t support it. Ours were on line breaks; we eliminated them by replace them with
/br in the code view.
We hit the issue with Chrome on Windows FWIW. Mac rendered perfectly.
There’s further discussion here. Looks like it could be an invisible character in your case.
Hi there! Is it possible you copy pasted your copy into a text box?