I'm actually not sure if this should fall under bug, or feature that could use a little tweaking. Say for example you have 4 Drannik Saboteurs. 2 of them are stacked, and two are still unstacked. The two that are stacked cannot be shared because you've shared them before, and if I collapse my stacks now I can't share any of the four.

I'd like to propose that when you condense your artifacts they sort into two piles, sharable and non-sharable. When you share an artifact from the sharable pile, it then automatically shifts to the unsharable one.

It could be that stacked artifacts can't be shared at all, but this could still work as a change if that's the case.