I sometimes have problems accessing corpse “nodes” as well (I think due to the layering of multiple AOEs on top of the body, perhaps?).

This seems to be the same issue that also makes other material resource nodes unavailable for a couple ticks of whatever Necro ground spells I have already cast.

I also notice that the corpse from Blast Bones often de-spawns faster than other corpses - because it is often gone by the time I switch bars to use Siphon on it - even though it is part of my normal rotation. It means I have to interrupt my back bar skill chain to get another BB going, even though I shouldn’t need to with the timing I have set up.

S.