I did a bit of testing with a jewelry item enchanted with legendary VR12 shock resist (1475 shock resist) and it does not appear to reduce damage for certain shock attacks from enemy players.

For example this item did not reduce damage at all from Mages Fury, Bolt Escape, Lightning Form, Endless Fury.

It does reduce shock damage from the "Lightning Flood," Twilight Matriarch and Unstable Familiar.

Anyone else have experience using shock resist jewelry?

In constrast, fire resist jewelry seems to reduce the damage for every class ability incorporating fire damage such as Lava Whip, Cinder Storm, etc.