Hittite cuneiform occasionally shows "plene" spellings, with extra vowel signs that might indicate vowel length, or show the height of back vowels, or distinguish homophones (like the French grave accent), or something else—it's not entirely clear.
However, from what I've read, Akkadian definitely had phonemic vowel length. Was this ever reliably/consistently distinguished in cuneiform, either by plene spelling, different glyphs, or any other method?
(Akkadian is the first language to come to mind that has both definitely-phonemic vowel length and a lot of attested cuneiform, but answers involving other languages are welcome too: I'm curious if any sort of cuneiform reliably distinguished vowel length, not just Akkadian.)