Definitely happens in Abyssea too. A friend of mine lost some drops because they dropped a few seconds after the items that came after it, which she couldn't pass because she was afk. I don't know about outside of that, but doesn't invalidate the point in either case.
I just have way too much stuff in general. I'm 80/80 on pretty much everything these days, so it doesn't matter what I carry in the field. While that may be mismanagement on my part, again it doesn't change the point. Sometimes it's not even 80/80 but 75/80. But then you wanna receive 6 items, and the trade is canceled because it doesn't work. Sure, you can /sack something, then hope to retrieve it again efficiently after, but that's just something that doesn't have to be imo.
It was just a possible suggestion to fix this, there's other things they could do as well, that would require little to no effort, like simply checking inventory status and allow only F=C-(I+L) items of the current pool to drop your inventory, where C is the inventory size, I the current amount of items you carry and L the amount of items you have a lot on. F, the result, would be the amount of free slots you have. These variables are already available and it would take barely any effort to import this setting.
Honestly, I don't even really expect that to happen, but I still felt like suggesting it. Maybe some day in the future, someone at SE will be bored enough to try it. Seriously, as a programmer myself I don't think it would be that hard to implement. There's a all these variables I mentioned should already be in the code, or could be easily calculated. There has to be a function that determines free inventory space already (currently being used for trading, lotting and obtaining quest rewards).
The entire change to the inventory I suggested could be summed up by using this formula, which calculates F, the amount of free inventory slots:
instead of the currently usedF(I, C, L, X, Y) = C-(I+L+Y)-X
Legend:F(I, C) = C-I
Looks a lot more complicated, but it's just some more additions (in a mathematical sense), it can be calculated in virtually zero time.C = inventory capacity/size
I = current amount of items/slots in inventory
L = current amount of lotted items in treasure pool
X = items currently being traded to party B
Y = items currently being traded by party B
F = amount of free items, result