So long as we understand that there is no such thing as a perfectly accurate scum tell then, yes, editing is a scum tell.
The only good reason to edit as town is if you’ve accidentally posted town-centric privileged information, like your role or who your fellow Masons are or gramma’s secret sugar cookie recipe. Bad formatting isn’t a good reason; not in this game.
Scum have lots more reasons to edit and they extend beyond accidental crossposting. Since they’re always lying*, the edit window gives them opportunities to notice that they’ve posted a contradiction or have otherwise upset their tissue of lies.
So, an edited post is more likely to be a scum slip than a town slip. If someone edits, they’re going to get the stinkeye (stinkfinger?) from me.
*Someone pointed out that the scum in this game actually get to scumhunt for real, which is going to make things a lot more difficult for us, at least in the beginning.