Does the target know that a silent / still charm spell happened if he makes his save?

[Genuine]

Imagine that a caster is invisible and casts a silent charm person. The target makes his save.

Does he know anything happened at all?

[The Sideromancer]

Yes.

CRB, magic wrote:

Succeeding on a Saving Throw: A creature that successfully saves against a spell that has no obvious physical effects feels a hostile force or a tingle, but cannot deduce the exact nature of the attack. Likewise, if a creature's saving throw succeeds against a targeted spell, you sense that the spell has failed. You do not sense when creatures succeed on saves against effect and area spells.

[QuidEst]

Silent/Still spells are still obvious, so it'd be noticeable even on a successful save.