category order doesn't order correctly for sub-category

[kmeyer]

I have set category order to "ordering". My site has arranged the top-level categories correctly, however a second level of categories appear to be sorted by some unknown (not alpha) sort order.  I notice that if I set it to "descending" it operates as expected, but when I set it back to "ascending" it uses some other order, not sure what.
Joomla 3.3.6, vm 2.9.9e.