I've just started using the GPU client and have just had my second wu stop like this, the first one stopped the same at 17% but finished OK when I restarted the client.
1st wu, 2730 (Run 8, Clone 96, Gen 18)
2nd wu, 2730 (Run 6, Clone 76, Gen 23)
[08:27:33] Completed 38
[08:35:16] Completed 39
[08:41:01] mdrun_gpu returned 50
[08:41:01] GPU was interrupted
[08:41:01] Folding@home Core Shutdown: INTERRUPTED
[08:41:03] CoreStatus = 66 (102)
[08:41:03] + Shutdown requested by user. Exiting.
Folding@Home Client Shutdown.