Working on Level 70 now, not a single red chest drop. Increased rate? Riiiight, Gumi. I believe you. And yes, it's a horrible raid. At least it gets easier after 70? I might have to use a Vigor Fruit to get there, I had to blow through four souls on Level 60. Honestly, if it weren't for my Hati friends I wouldn't have made it past 50. I couldn't pull one for myself, so it's really helping me out.
Oh, I experienced a weird glitch last night. It came right after I did the 18AP Mage enhancer quest, where all four chests dropped. I got the demon invasion right after and jumped into it, only the field was grass [like in the Mage enhancer quest] and only four waves. I immediately got a "Time Up" notification, and got four chest drops again, those being the enhancer drops from the previous quest. I didn't lose a soul which was nice, and I got additional Mage enhancers out of it, so not bad. Lost the helper, though.