While I refer to the Guardian's "Shard Guardian" ability, it's likely that the Wizard's "Shard Sense" works in the same manner, I just haven't tested it.

When you take the skill, it reveals all of the shards on the map. If you look, this is the result:

The shard is actually giving vision, as seen by the fact that I'm able to see the monster pack next to it. However, if I save the game and then reload it...

I still have the terrain revealed, but the shard is no longer actively creating vision, so I lose the ability to see any units near them. Either the shards shouldn't be granting constant vision in the first place, or that vision should persist through a game load.

While seemingly minor, it does have a major impact on the implications of the ability. One of the odd quirks of the shards giving vision is that you can use them to speak to all of the rivals on the map as early as turn five. Pretty rad.