Spells like Regeneration that can be cast on a unit outside combat and have a check to determine how strong it is via actively held shards do not update when you get more shards. And you can't overwrite them and perhaps I am just dumb, but I can't figure out how to cancel the spell so I can refresh it so that it will update.

For example, casting Regeneration on yourself at the beginning of the game will give you +1 health per tick in combat and per season. When you get a life shard claimed, it will remain +1 per tick but any new units you cast it on will get +2.