This is very similar to the sniper bug that I know is known, but I've found that Regulus' normal arrows are also capable of following in the player anywhere on the map once fired. This was demonstrated most graphically when I once teleported as he was firing at me, and was zoomed out so I could see the whole map. I watch as the arrow booked its way all the way from the left to right sides (units on my side were there so it was all visible), to impact on me. The arrow pulled off a few rather impressive turns in the process; for a second I thought Regulus had some awesome missile attack I didn't know about. I've also see the arrows pull a few very tight close range turns, usually if I just walk across him as he's firing. The arrow starts out pointing forward, and then loops around in a very tight curve. I know he's supposed to have an angelic crossbow, so maybe that's intentional, but the cross-map shots are a bit much. I suppose this really just broadens the scope of the issue, rather than being anything new, but I though I'd post it anyway.