Is the Amagi Challenge no.18 bugged?

Question

I'm trying to get past Yukiko Amagi's challenges, but I'm stuck at challenge no.18.

The combo I need to perform is:

Standing C
Crouching C
Agi (quarter circle down-forward + A)
Agidyne (quarter circle down-forward x 2 + C)

The problem is that Yu always seem to recover mid-combo after my Agidyne connects.

I've looked at the demonstration a few times, and it looks like Agidyne must connect before Agi's flame appears, which I pulled off a bunch of times already, but Yu always recovers then. Whenever I manage to pull the entire combo off (Yu doesn't recover mid-combo), it seems as if the combo itself wasn't quite right.

According to the demo, Amagi's Persona would trap Yu in some sort of flaming tornado while staying on the ground during Agidyne. When I pull off my combo, my Persona is actually flying diagonally upwards.

By the end of Agi, the combo will end with 19 hits; Agidyne needs to launch between hit 18 and 19, but Yu always seems to recover at the exact moment the 19th hit connects.

I'm beginning to suspect something is bugged here. Is the input for the last part of the combo really 2x down-forward + C? What am I missing?

Answer 1

I believe you need to hold down the C button input when performing Agidyne, and continue to hold it until the animation is fully completed. The in-game command list doesn't tell you this, but holding down the button when performing the move will alter the properties of the move slightly; namely, it looks like the startup time of the move is shortened, which may be the important part for making this challenge's combo work. I've heard (but cannot presently confirm) that it may also add vacuum properties to the move as well.