I'm actually having issues with Titan hard precisely because of that line. I've been 2-3 steps away (4, once) and still get hit by it. The lag and latency issues from beta are still there and is only more pronounced on Titan where it's instant kill. People from end-game LSs are reporting it can be a huge problem for people from certain regions, and I'm seeing it too.
Here's a trick for normal mode, though:
You can run towards him. If you can get close enough, it won't knock you off the edge, even during the second part of the battle with the smaller platform. This way, you do take a bit of damage, but it's better than being killed.