I've had lag before, but only once or twice with smites. I thought I missed originally, but it was just lag. The smite is from a mod package and known to rarely lag. I'm not sure what's going on with your Wyll. It might be some status effect /debuff/item/etc interaction. Issues can certainly be specific to spells.
I've come back to this game after months and still have the same old bugs I've always had, now with some extra. Larian probably won't fix it. It seems the only thing they've fixed was the combat bug that could hardbrick your save in act 1. I mean, that's great because it was a run ender, but really...