Herald of Ice Working Fully When Only Active in Second Weapon Set

Herald of Ice is causing shattered monsters to explode and deal damage even when it is inactive on the weapon set being used.

To reproduce the bug, you have to slot in Herald of Ice, activate it, and then disable it in one of your weapon sets. Swap to the weapon set where it's disabled, and you'll still see ice explosions from shattered enemies, and even chains of explosions if using Polcirkeln to shatter chilled enemies.

Interestingly, it seems like the Herald of Ice is using the passive tree from the weapon set it is active on. I say this because I have substantially more Area of Effect on one weapon set than the other, and the difference in explosion size was very noticeable when I tried reproducing the bug using the weapon slots reversed from when I discovered it. To clarify, having more AOE on the inactive tree (where herald of Ice was active) caused the larger explosions.

I can't tell which weapon the Herald is using to calculate damage, but there's absolutely no question that it's causing explosions even when it's clearly only active on the currently inactive weapon set.

Sorry I don't have time to post screenshots, but (un?)fortunately this one is super obvious and easy to reproduce.