I don't know if the issue is related to specific artifacts or not, but sometimes when I sell a few of a certain artifact the artifact will disappear from the list. It's only when I go to another tab, then back to the Trade tab that I see the artifact back in the list with the remainder.

Here's one of the artifacts that it has happened to me with: Spy Probe - Resources

Has anyone else come across this issue?

not particularly, but my page refreshes often when i do that, so, no...

Yes it happens to me all the time. Just go to a different tab and come back. Just one of those 'bugs' that has a work around so I hope Dan isn't spending time on fixing it - I rather he continue to improve the game.

save a click.. you don't even have to go to another tab... just click on Trade again while you're already on the trade tab...

That's the solution I use now too.

of course it's just a workaround... we still need Dan to actually fix the issue itself... but since we have a simple workaround, i'm sure this is low priority

something very minor, but still shouldnt happen. it seems easy enough to fix. i expect this to be sorted before 2012

i expect whatever comes after 2012 to make this issue moot