does unearthed arcana’s mystic’s “charming presence” ability let someone know after they’ve been charmed?

in the mystic booklet for UA in 5e the description for charming presence is as follows:

Charming Presence (1–7 psi). As an action, you exert an aura of sympathetic power. Roll
2d8 per psi point spent on this ability; the total is how many hit points worth of creatures this option can affect. Creatures within 30 feet of you are affected in ascending order of their hit point
maximums, ignoring incapacitated creatures, creatures immune to being charmed, and creatures engaged in combat. Starting with the creature that has the lowest hit point maximum, each creature affected by
this option is charmed by you for 10 minutes, regarding you as a friendly acquaintance. Subtract each creature’s hit point maximum from the total before moving on to the next creature. A creature’s hit point maximum must
be equal to or less than the remaining total for that creature to be affected.

let’s compare that to the charm person spell. it explicitly states in the description:

When the spell ends, the creature knows it was Charmed by you.

pair the comparison with the fact that there are no components (pg.9) to psionic casting, and i don’t see why someone would know they’re being charmed.

is there any reason that someone may know they were charmed on a successful save from the charming presence ability? would the creature know it was charmed after the fact?