Bug with voltaic mark, double shocks and consuming shocks.

I was testing things with a friend of mine and came up to this bug.

Here's the setup that matters :
-Stormweaver with double shock ascendancy
-Cast on Shock setup with Voltaic Mark (20Q) & Lightning Conduit
-Orb of Storm with overcharge
-15% shock magnitude on tree

The boss gets applied 2 23% shocks from Spark

The Cast on Shock setup triggers, applying the mark and consuming a single shock

The Orb of storm is able to apply a 38% shock

Both values are amplified to respectively 33% and 55% shock if the mark is on that shock

The bugs :
It seems Voltaic Mark only applies to a single shock and not both, could be intended

The surely unintended part is that if only a single shock remains on the target after one of them is consumed, the second shock - being now the only shock present - is NOT amplified by the still present Voltaic Mark.

I can provide video footage if needed. Hope this helps !