Thank you for this add-on, it saves me a lot of time!
I think I've found a bug: in the add-on settings, the checkbox to keep/remove the ?utm parameters is not behaving as it should. Though I unticked that option (https://i.imgur.com/nqIR24h.png) and then clicked on "save", it's still removing the parameters anyway. This was already happening before the last update.
When I shorten the same URL directly in is.gd, the parameters are kept, so I know the problem is not there.