MCH oGCD abilities not always activating when pressed

[RichardButte]

Date & Time: Any
Frequency: Often
World name: Any
Character name: N/A
Retainer name: N/A
NPC name: N/A
Monster name: N/A
Class/Level: MCH, possibly all levels, but especially 60+
Party or solo: Either
In-game time: Any
Area and coordinates: N/A
Housing: N/A

MCH's abilities that are off the global cooldown can fail silently if used in rapid succession (or sometimes not rapid at all).

Note that I do not have this issue on NIN, which has numerous oGCD abilities as well.

Steps:
1. Play a MCH, 60+ for the ideal setup.

2. Attempt to use several GCD abilities in a row, as often as you can (including attempting to place turrets).

3. Over time, you will notice that the game will silently fail to execute some of these abilities. I say "silently" because you will press the button, the corresponding icon on the hotbar will flash, indicating that you have pressed it, but the ability will fail to execute.

Ideally, there would be better tracking of buffering of inputs so they'll still activate as soon as possible and in the order they were pressed.

Failing that, however, the game should at least generate some type of error message to inform the player that the ability was pressed but not executed.

Here's a video of it happening twice: Rapid Fire is pressed but fails to execute at 15 sec, Gauss Round at 30 sec.
https://www.youtube.com/watch?v=LBuShjLJChc