This has happened to me twice already, I've been gathering/crafting mats for Grand Company seals only to find the quotas filled within hours of being placed. Most recently, I crafted a bunch of hempen cloth for this week, only to get the message that the quota has been filled, I now have a stack of cloth that I doubt will sell, and wasted about 30k on the grass to craft it from, and before you complain that I'm just hating, this happened today, less than eight hours after the GC made the item request. The quotas are obviously inadequate, considering the most valuable ones are being filled in less than a day, with a weekly reset.
Therefore, why can't we just get rid of the fixed quota? At present, it just locks out people who can't be on all the time.