The "load build queue" is broken, or at least it was with the 1.09 patch. I didn't try with the new one yet.
Basically, if your build queue includes any building, loading it will give you seemingly random mix of units/buildings that were not on your original queue.
It does work fine however if you have only units in the queue.
I used it in the past to build military units in my core cities once all the useful buildings are done.