Lighting Warp + Less Duration not working? Bug or intentional?

I've been trying to use:
Lighting Warp + Faster Casting + Less Duration as a movement skill but the Less Duration gem doesn't seem to increase the duration between cast and teleport. The tooltip correctly displays the 'reduced duration' from leveling LW, the actual cast time is faster but the Less Duration support gem doesn't seem to do anything. LD gives a 40% reduction and that should make a noticeable difference.

I cross-checked with the wiki on LW and it specifically states:

"

The Less Duration gem will also reduce the time between the cast and the actual teleportation. It is not possible to completely eliminate this duration because there is a hidden 0.1 second delay added to it.

Am I missing something here or is this a bug?