We have the issue that Bamboo 4.0 build 2906 sometimes fails Maven build tasks in the middle of their execution, and then complains that it could not find a "build success" message in the last 250 log entries.

It does not seem to occur if we stick to just one local agent. With multiple local agents and multiple build running at the same time, however, this problem occurs quite often (every 20-30th build roughly).

Here's a sample log excerpt, as you can see that Bamboo is failing the task even though the Maven build process obviously has not finished yet.

...
build 14-May-2012 17:06:05 T E S T S
build 14-May-2012 17:06:05 -------------------------------------------------------
build 14-May-2012 17:06:05 There are no tests to run.
build 14-May-2012 17:06:05
build 14-May-2012 17:06:05 Results :
build 14-May-2012 17:06:05
build 14-May-2012 17:06:05 Tests run: 0, Failures: 0, Errors: 0, Skipped: 0
build 14-May-2012 17:06:05
simple 14-May-2012 17:06:05 Failing task since text 'BUILD SUCCESS' was not found in last 250 log entries
simple 14-May-2012 17:06:05 Finished task 'Maven 2.x'
...