Shock ability is weird

[Zetcial]

I haven't played warframe in a while, so I understand that this might be a stupid question to ask, but why do some enemies just doesn't any damage from Volt's damage abilities despite showing that they're affected by them? (Shock in particular)

[Donitsi]

Depends on their level and what faction you are fighting.

Shock deals 200 Electric damage (Max rank ability with 100% Strength) which barely sratch enemies when their level goes 5 or higher.
https://warframe.fandom.com/wiki/Elite_Lancer

If Wiki is correct, level 5 Grineer has 192 health and 211 armor (which is 25% damage reduction from armor). Electric deals neutral damage to Elite Lancer which means at this point Volt becomes more Crowd Controlling (CC) Speedy boy. His 4th ability deals insane damage though when you know how it works and what mods you need.