The Walking Dead: Season Two

for me the issues with unlocking wasn't random (that doesn't change the fact that it was still annoying).. but what caused it for me was my controller turning off (100% correlation between that and no achievement popping throughout my playthrough)

i hope this helps someone (there could be other random reasons i just wanted to share that i caught onto my own personal reason for it not working while other people have told me that not pausing and/or not quick resuming was the trick for them)