Fill command bug with state

when i do for example:
/fill -780 4 -983 -776 4 -982 glass 15
It fills it in with glass 0. It does it with every state of glass.
When you already executed /fill -780 4 -983 -776 4 -982 glass 15 and then fill it in with /fill -780 4 -983 -776 4 -982 glass 5 it says:"No Blocs Filled"