Swain cancels his movement when you press R, doesn't have a cast time anymore but interrupts his movement, which almost killed me on a couple occasions.
EDIT: The hotfix is out in EUNE, I posted it here so Riot sees it, on EUNE it wouldn't have been seen.
Riot knows. They're fixing it in the hotfix.
You appear to be correct, the hotfix has gone live and Swain's ult still cancels movement. At one point Rioters were saying that change couldn't go out in the hotfix but then Meddler and patch notes were saying it was going out with the hotfix. It's possible that there was a miscommunication and it really wasn't possible or that it just fell through the cracks.
Fun fact though: now that deathfire touch works properly, Swain's Q applies the full 4 second single target deathfire touch. I'm not sure if that's intended since it is a multi-hitting ability and capable of hitting multiple targets/champions over the course of its duration, but for now at least that means an additional 25% AP ratio after they leave the zone over 4 seconds, in addition to the extra 6.25% ratio every second while they're being attacked by beatrice (maximum of a 50% AP ratio if they sit in the entire thing)
More people should Upvote this. This is EXACTLY the case and Riot should be made aware of this!
