In my opinion, the problem probably comes from the forward slash (/) which messes up the key reading, but I don't know for sure.
On my end, I've coded a Python script that automates the translation via the Google Translate API. Since you've done an exceptional, painstaking job tracking down these lines, would you mind sharing all the English keys you've already found? It would save me a massive amount of time so I can feed them directly into my script!
Thanks a lot!