The title aside this is a maybe but I hope its what works for everyone still trying to get this because I just got it.
If you have your lights off by the time you get into the storm, turn a light on THEN turn it off.
I don't think the game is registering that you have your lights off or have "Turned Off" your lights if you go into the storm with your lights already off.
Reason why I'm sharing.
I've been trying to get the perfect dark for a good while. Every single time my lights would already be off by the time I got into the storm. Rolled around for like 30mins and NOTHING. I did this a BUNCH of times.
This time around I went into the storm with all my lights off and decided to turn on and off one of my lanterns next to the wheel on the sloop. Immediately after turning off the light I got the doubloons and gold.
Again, I don't know if this will help everyone, I'm just hoping it does.
Good luck everyone
EDIT Basically, either wait to turn off your lights when you are IN the storm or if you go in there with your lights already turned off then turn on a lamp and then it right back off.
EDIT Mentioned by @NeedSmokes
Should also add that this will only work when the ships bell is ringing to alarm you that you are in the heart of the storm.. Being on the outskirts of it won't help.
EDIT Verdict is that some players are getting, some are STILL not getting it. For those that it doesn't work for I am sorry this couldn't help you.
EDIT I forgot to mention that I was rolling around in that storm for a good while before I decided to try to turn off my light and back on again, maybe that will help??
EDIT @Captain-Coel has mentioned that he has had it work on both of his pirates with the lights already off when he approached the storm.
Hey @Captain-Coel - what region are you in? I'm center Texas. I wonder the issues are region based like that one time when loot wouldn't count for some regions but worked fine for others.
