Temporal Rift sometimes fails without an apparent reason

On perhaps 1% of casts or less, temporal rift will activate and play its warping-between-afterimages animation, but my character won't be moved and my health/mana won't reset. I've seen this happen even after clearing a pack when there was nothing around to interrupt or interfere. I haven't noticed anything that seems to trigger the condition.

Temporal Rift always do it when i hold left mouse button(move only) and press Temporal Rift button.

thanks for that now I know