When typing two dashes (--)back to back Editorial does not type the second dash, but instead deletes the character immediately before the first dash which changes to a different style of dash (—)
So instead of this <!-- (or this <!— thanks to iOS native smart punctuation) I get this
<—
As far as I can tell from toggling things on and off this isn’t caused by any of the General settings (character pairs etc) or a rogue TextExpander snippet.
I am indifferent to the type of dash, it’s the deletion that’s an issue.