As the title says; the copy of "Symphonic Charm" played via "Echo" only applies the base value of '2' and ignores you 'Symphony' stacks.


Reproduced via dev console on turn 1 by playing:

"Prelude"
"Prelude"
"Prelude"
(Just to get 'Rythm' out of the way)
"Symphonic Burst"
(You have 4 'Symphony' staks)
"Echo"
"Symphonic Charm"
(First copy applies 6 'Captivation' to total of 6 and raises your 'Symphony' stacks to 6;
second copy applies 2 'Captivation' to total of 8 and raises 'Symphony' stacks to 8
)

I would have expected the target to have a total of 14 'Captivation' stacks (6 from the first copy and 8 from the second)