Just now, I went to go accept a trade request. I have a Harbor and have 5 trade slots (as indicated on the top of the screenshot). However, only four were filled, but I was told that the limit had been reached.
As you can see, I am told "You have 0 out of 5 Trade Slots Available" even though I have four slots filled - also shown on my nation display page: http://www.cybernations.net/nation_drill_display.asp?Nation_ID=351623
Thanks in advance.