sparks bugging out

when casting sparks at some point no more sparks come out when using the skill. the skill is being used with animation and mana cost but only one or two projectiles come out with a bugged visual. i have force of will ascendancy passive and cast speed nodes. projectile duration is 4.99 seconds, projectile speed up to 223%, cast speed starts at 4.27 casts per second and the animation bugs out at around 4.55 casts per second, after which it doesn't produce the correct ammount of projectiles anymore, not even triggering wildshards 2 support. literally suffering from success.