Yup, left it running for 5 hours, it was stopped again.
It's like if it detects no computer activity, mouse movement or something, it just stops after a short while. As long as I am doing something on the computer it keeps downloading, well over 5 hours.
Back to deluge I guess.
Edit:
Just found the log, it says it stopped because of "data error (cyclic redundancy check)".
The drive is a one month old SSD, there are no problems of any kind with other software.