Flash to focus not workin on Lollipop roms topic

if Anyone knows why on any single Lollipop rom (including stock android L on htc m8 GPE) the camera wont flash to focus on low light situations... please tell me. On sense roms the camera flash to focus normally (low light situations).
its very annoying take pictures with the m8 and lollipop roms.
this doesnt happen with nexus 5, galaxy s5 (custom lollipop rom), or the nexus 6