Warrior - fissures slammed bugged?

Maybe im missing something, but:

1) fissures sometimes glow instead of erupting after youve slammed for a while, whats this effect and its not listed in the tooltips?

2) this also happens from the first slam on for basically every subsequent slam, also with leap slams

https://www.youtube.com/watch?v=wLesjJtJajk


Bug or any1 know why and when this happens?

duh dynamic culling...