This is a problem I've been encountering more and more; likely due to the increase in the amount of people killing trains of mobs AoE style.
What's apparently happening is that so many chests are landing on the ground in Abyssea, it's keeping others from getting chests at a sufficient rate, even with maxed pearlescent light. We already know why it's happening; we're used to it from when Treasure Caskets were introduced. Since chests are so much more important in Abyssea though, I think something should be done about the problem now, because it's only going to get worse as we close in on level 99.
I'm not going to go ahead and say that I've got the perfect solution here... just brainstorming ideas that might possibly help. Feel free to add your own contributions, just please keep retarded suggestions to yourselves, such as "nerf chest drop rate for AoE burns" or "get rid of PS2 support" or "I am the walrus" or what have you.
One idea floating around in my head is to reduce the amount of time (currently 3 minutes) that a chest will stay on the ground if the limit is being approached. Not by that much; maybe down to 90 or 120 seconds minimum. Not only would this help get rid of those pesky ISL or temp chests that nobody cares to open faster, it would serve as an actual notice that the zone is being hammered with chests at the moment, and that drop rate might be reduced.