Friend cannot see my trade depot items.

I believe this to be a server lag issue rather than an actual bug.   This has happened to me.  I'm playing a game on my phone and my daughter is playing on her phone.  We often trade things back and forth.  When this happens to us this is what we do.

After placing the item for sale, close the sale window, open it up again, close it again.  Collect any item.  This can be done through popping a bubble, collecting from one of your stores or even collecting taxes which we did today.  Then open and close the sale window one more time.  Each and every time that this has happened to us, when we close that sale window the final time, the other phone can now see the item for sale.

I believe this is the same reason why some items don't sell very fast that would otherwise fly off the shelf.  The server did not recognize the sale.  Where it may fix itself in time, you can speed it up by doing another action that requires communication to the server.  Since EA keeps a copy of your game on the server, just collecting another item forces communication to the server.

There are other times that we have no issue at all and can see the items immediately, but it would appear the issue happens only during prime playing hours and not at off hours when fewer people are playing which is what lead me to the conclusion that it is a server lag issue.