Shyvana Visual Burnout bug

So on some of shyvanas skins (from what I noticed all but darkflame)

Her burnout will have periods where it shows constantly but then periods where it will not show at all, not sure if this is intional or not, but yeah I feel this is a problem, and if this was on purpose I find it bad for well, the fire animation is to display to the enemy "hey im dangerous stay away from me" and if the fire animation does not show how can said enemy receive said warning?