In a NBT Path, an Array Tag can't be followed without intermediate node by a Compound Tag.
Example with this NBT Structure: 

{Foo: [{bar: 0b}, {bar: 1b}]}

This path is syntactically invalid:

Foo[0]{bar: 1b}

Whereas we can do

Foo[0]
Foo[0].fooz{bar: 0b}
{bar: 0b} (if bar is in the root tag)
Foo{bar: 0b} (if bar is a child of Compound Foo)

independently.

This is thus inconsistent.