I have a BQ 4.5 (stable) and, I think it focuses properly, at least as best as it can since the specs are not the best.
Also as @Keneda says, manual focus seems to readjust the image.
Maybe is damaged.
This thread is beging to go a little OT as it was and is in a thread for BQ E4.5. For general battery discussions this is not really the right thread. Please only post here if directly about the thread topic.