Sarog's Egg quest has been broken since Day 1.  I wish they would fix it.  There's like only one perfect way to do it...any deviation and it won't work.  It's only worked for me once in ten tries.

There was a bug fixed a few builds back where if you didn't complete a fetch quest in one sitting (not saving/loading) then it would break.  My guess is that the condition tracker is using the unit that triggered the quest and will ignore any units, besides the original, that try to return the item.

Will investigate today and get back to you.

Update: I think I found the issue...the trigger was grabbing the unit that just stepped into the trigger tile, but instead of doing a lookup via unitID (which was passed in) it did it by Index (position in the array)...two very different things. It would always work for your sovereign though because thats always the first unit in the array, and any other time it'd work would have been dumb luck.

This will be in the next update.

I used to--maybe back in September. Since then, if I decide to pursue the quest, it has not been an issue.