Working out a special software-related battery problem

I agree to the category. I had in mind, that there is a categorie about bugfixes, but I didn’t found it.
And Yes, I mean software at any kind. But the deeper the bug is, the more phones might be affected, not only fairphones.
And I forgot to say, that I updated to 1.8. It was a bit bumpy, but it worked. The behavior described above happend before and after the update.