You hit famous "finish file present too long" Boinc bug. Look like that for unknown reason, Boinc tried to start (most probably restart same one) task while another instance was still running in same directory. Meantime, first copy successfully finished and uploaded valid result file, while Boinc was confused that something is still running and reported an error status to server.
I see that LLR process was restarted many times. Do you have a option like "Pause computation when computer is active" turned on? Boinc has a design flaw when termination of task at specific moment will trigger race condition - Boinc will not notice that task has already finished, restart it from beginning and finally abort with "finish file present too long" error.