Can't Trade Seed Box

[Leon]

You can't trade the seed box through the trade system.

I'm guessing it's doing the same weight check as a wooden box and finding it too heavy:

[Jack]

A seed box weighs 60 stones. Are you sure the recipient was just not able to carry that much more? There's nothing special I can see about the seed box that would disallow trading - it's just 1 item @ 60 stones.

[Leon]

Yup. I was able to drop it and pick it up with the other player.