Shockburst Rounds Pulse not triggering off second Sorceress shock

I have observed multiple times where the second shock that the Sorceress applies via Strike Twice does not appear to proc Shockburst Rounds. I haven't been able to verify if this occurs when the first falls off while attacking. I have though seen if you attack with Shockburst after the first has fallen off then the Pulse does not occur. I have a small clip of it occurring while fighting Chimera but I have seen it on other fights as well.

Clip: https://youtu.be/hIxJ_VJ_EpA

Reference #: 798,550,480