Bard Straight Shot Free Movement while Casting

Time: Any
Frequency: Always
World name: Gilgamesh (applies to every Bard)
Character name: E' P'
Party or solo: Solo or Party
Area and coordinates: Anywhere (video shows Lavender Beds)

Steps:
Under the Bard's Wanderer's Minuet, if your heavy shot lands a proc, and you use straight shot right away, it will not instantly cast straight shot, but go under casting, AND the user is able to freely move while under the casting time.

In this case, it also means that you cannot cancel your straight shot under this effect.

Here is a video:
https://dl.dropboxusercontent.com/u/98915819/SS-Bug.mp4

It's been around ever since WM, but I never thought it would become as annoying as it is wanting to cancel the skill to cast something else :P.

Edit: Yes, I know about the 1-2 second 'early move' before the cast finishes, but this is straight from the beginning of the cast time.