They are vanilla fertilized eggs.
I checked out DroppedItemGeneric_FertilizedEgg that you pointed out. Sure enough, in the construction script graph there is an orange-coloured “Parent: Construction Script” which is “the place to spawn components and do other setup.” according to the hover-over text.
Which is non-exposed code… and must be failing due to the lack of valid tamed actors as the source. 
Maybe the devs could tweak the code and source randomized stats from the dinosaur parent blueprint when there is no actor??? Somehow I doubt this request will get much priority but you never know!