In the Quartus II software version 15.0, a legality check issue in the Fitter causes an abnormal exit during the Fitter stage when the
listen_to_nsleep_signal parameter is explicitly set to true but the nsleep port is not connected.
This issue applies to designs targeting the MAX 10 ZB16/25/50 device only. The Quartus II software should generate a user error, but causes an abnormal exit instead.
You might encounter the abnormal exit if you use an input buffer atom, or Altera's general-purpose I/O (GPIO) Lite to construct your IP.