Aetherflow starts cooldown but doesn't add Stacks

Thread Title:
Aetherflow starts cooldown but doesn't add Stacks used for casting spells which requires aetherflows.
Basically, in random situations, usually after another instant cast spell (Ruin II), Aetherflow fires, trigger its cooldown but doesn't recover mana and doesn't give you aetherflows (3).
This is a huge issue, basically destroying summoner dps for 60 seconds.

ISP:
MC-Link (Italy)

Type of Internet Connection:
DSL

Internet Connection Speed:
7Mbit down, 512 Kbit up

Date & Time:
Random situations.

Frequency:
Sometimes

Character Name:
Quarion Silverfrond

Race:
Race of your character when the issue occurred.
Miqo'te M

World:
Shiva

Class/Level:
Arcanist (Summoner) Lv. 50 (but happened also earlier)

Area and Coordinates:
Everywhere

Party or Solo:
Both

Steps:
- Cast as often as possible, Aetherflow, after something like Ruin II, in some random situations the issue will happen