2x Drop Event

Too right. I hope they'll fix it. But I doubt it: neither Entitlement's 2x Drop works.

Yes it does. The way you can tell is to find a monster that drops ETC items more than 50% of the time. (Which is most of them.) Then use 2x drop and every kill will drop an ETC item. Family 2x drop works... I used it on 100-year-old Bellflowers to get that 1000 ETC secret reward, and I didn't once have a kill with no ETC drop while I was on the 2x. 1.5x also worked fine. I also got their card and more equips while I was using 2x, but that isn't the proof of it.

2x drop cards work differently than 2x drop events. 2x drop events don't modify the meso amount.

Also, the amount of equips you get in a single session can vary so much... It's not really surprising if you get a lot of variation in equip drops, since there's such a low chance already. If you take statistics, read up on the Law of Large Numbers... Essentially, you need more trials to go toward the true average rate if the rate is very low or very high.

EDIT: I'm not denying that 2x drop used to not work. But family 2x does work right now.