org.pentaho.di.core.util.StreamLogger IOException

I have what I think is a logging issue running a job. At an execute a shell script step, I am getting:

- Starting entry [Curl - sumtraf]
INFO 12-08 13:14:44,888 - Curl - sumtraf - Found 0 previous result rows
INFO 12-08 13:14:44,888 - Curl - sumtraf - Running on platform : Linux
INFO 12-08 13:14:44,935 - Curl - sumtraf - Executing command : /opt/log/shoppertrak/kettle_af096400-0372-11e3-93b5-832ee142cbaeshell
INFO 12-08 13:14:44,975 - Curl - sumtraf - (stderr) % Total % Received % Xferd Average Speed Time Time Time Current
INFO 12-08 13:14:44,976 - Curl - sumtraf - (stderr) Dload Upload Total Spent Left Speed
INFO 12-08 13:14:44,976 - Curl - sumtraf - (stderr)
INFO 12-08 13:14:45,302 - Curl - sumtraf - (stderr) 0 0 0 0 0 0 0 0 --:--:-- --:--:-- --:--:-- 0
INFO 12-08 13:14:45,315 - Curl - sumtraf - Command /opt/log/shoppertrak/kettle_af096400-0372-11e3-93b5-832ee142cbaeshell has finished
ERROR 12-08 13:14:45,317 - Curl - sumtraf - (stderr) java.io.IOException: Stream closed
at java.io.BufferedInputStream.getBufIfOpen(BufferedInputStream.java:162)
at java.io.BufferedInputStream.read1(BufferedInputStream.java:272)
at java.io.BufferedInputStream.read(BufferedInputStream.java:334)
at sun.nio.cs.StreamDecoder.readBytes(StreamDecoder.java:283)
at sun.nio.cs.StreamDecoder.implRead(StreamDecoder.java:325)
at sun.nio.cs.StreamDecoder.read(StreamDecoder.java:177)
at java.io.InputStreamReader.read(InputStreamReader.java:184)
at java.io.BufferedReader.fill(BufferedReader.java:154)
at java.io.BufferedReader.readLine(BufferedReader.java:317)
at java.io.BufferedReader.readLine(BufferedReader.java:382)
at org.pentaho.di.core.util.StreamLogger.run(StreamLogger.java:57)
at java.lang.Thread.run(Thread.java:722)




but this only happens sometimes. I can run it 6 times in a row, 4 times it works, twice it fails.

I have specify logfile and append logfile checked and row level logging all set in that step.
Any ideas?