delete of nested array is in consistent

[Peng Yu]

See below. I'd expect the second one should also print array. Is it a bug?

$ awk -e 'BEGIN { delete a[""]; print typeof(a) }'
array
$ awk -e 'BEGIN { delete a[1][""]; print typeof(a[1]) }'
unassigned

-- 
Regards,
Peng