Issues, Workarounds & Localization

On further inspection I've identified that the

Module Siege Warfare Link - Shield Efficiency II

Isn't applying to ships at all.

This module is Broken!

Whoops CCP.

Hopefully its an easy fix for you guys.

did anyone create a ticket? like a bug report or a support ticket? link this post for them in the ticket if you don't want to retype everything but they don't read this forum (probably not true, but they won't act without a ticket)

I'm afraid your video doesn't really show much. You don't show that your fit was cap stable to begin with, nor does the ~2 minute video show much in terms of you running out of cap, just dropping. You're also not staggering your modules, meaning you have a disproportional large drain when all your modules cycle at the same time, dropping you way below peak recharge.

Whenever you change boosters you need to revoke and reset the boosts from the top-down.

If you add a fleet booster (which requires someone with the appropriate skills in fleet command if you weren't aware, it doesn't work unless you have a valid fleet commander in fleet) you'll need to revoke all wing and squad commanders and reset them wing commanders first, then squad commanders. If you don't, then you'll see such errors are you describe above, with boosts not being passed along properly throughout the fleet.

I did some testing myself, prompted by your claim. Sadly found nothing wrong. Here are some screenshots.

http://i.imgur.com/nN6v6jw.png - My tweaked setup, barely cap stable.
http://i.imgur.com/LidN6Y4.png - Modules staggered I drop to predictable 33 - 40%, never below (ran this for several minutes).
http://i.imgur.com/t3PNI49.png - Cost without any links running is the base.
http://i.imgur.com/2qtquBL.png - Turning on just the shield efficiency link makes the cost drop.
http://i.imgur.com/Cr9BC5y.png - Predictably, my cap remains much higher with the lower activation cost.
http://i.imgur.com/c6ZGqHF.png - Turning on the active shielding link reduces the cycle time.
http://i.imgur.com/EHu237z.png - I let this run for several minutes and predictably remained at the usual 33 - 40% levels.

So as far as I can tell, the shield efficiency link works just fine, alone as well as combined with the active shielding link. Most likely this glitch of yours is the result of something else, your lack of staggering or an erroneously setup fleet.

Posting again to concur with Scarlett about a bug, after having spoken to a friend who've experienced it too and explained the steps to reproduce it.

Did some more testing, doing exactly that, moving the booster from Squad Command to Wing Command and back, encountered the very bug you're describing. It's reproducable every time doing this:

Use two characters, one in any kind of ship (A) and another in a boosting ship (B).

1) Put B as Squad Commander (they automatically get Squad Booster) and A as a regular squad member. Valid fleet structure.
2) Test links, they all work fine.
3) Move B to Wing Command (they automatically get Wing Booster) but links aren't passed because you don't have a valid Squad Commander anymore.
4) Move B back to Squad Command (they automatically change to Squad Booster) but now you encounter the bug.

The bug seems to make a ghost link of one of your active links at the time. It was the resist link in my case, but I tried it a few times and it wasn't always the position or cycle stage that seems to determine it. Either way, it's not bound to the shield efficiency link per se, it's just that something breaks the fleet's entire boosting chain at that point.

This "ghost link" remains active even though you revoke boosts, move the booster around, turn off the actual link in question on B ... nothing has an effect. In my case, the resist boost persisted until I kicked the booster from fleet. At that point, the ghost link effect disappeared.

Keeping the same fleet, inviting the booster did not fix the issue, as Scarlett pointed out; It's broken for the fleet and can only be fixed by simply disbanding the fleet and making a completely new fleet.

Hopefully with a step-by-step reproduction guide the devs can trace the errors occurring and fix it.