Why does Bamboo show the last build output in the live logs.

Lets say a build has previously failed and hen we kick off a new instance. The live logs have data like this

7-Jan-2010 05:14:07 BUILD FAILED
17-Jan-2010 05:14:07 File...... /opt/j2ee/domains/atlassian.com/jira.bamboo/webapps/atlassian-bamboo/data/bamboo-home/xml-data/build-dir/JIRAFUNC-JDK16BATCH06/maven.xml
17-Jan-2010 05:14:07 Element... maven:reactor
17-Jan-2010 05:14:07 Line...... 1293
17-Jan-2010 05:14:07 Column.... 19
17-Jan-2010 05:14:07 Unable to obtain goal [jira:cargo-func-tests] – /opt/j2ee/domains/atlassian.com/jira.bamboo/.maven/cache/maven-test-plugin-1.6.2/plugin.jelly:289:58: <fail> There were test failures.
17-Jan-2010 05:14:07 Total time: 14 minutes 4 seconds
17-Jan-2010 05:14:07 Finished at: Sun Jan 17 05:14:07 CST 2010
17-Jan-2010 05:14:07
17-Jan-2010 05:14:07 Build process for 'JIRA Functional Tests - HEAD - JDK1.6 Batch 06' returned with return code = 70
17-Jan-2010 05:14:07 Parsing test results...
17-Jan-2010 05:14:21 Failing build since 1 failing test cases were found.
17-Jan-2010 05:14:21 Running post build plugin 'Artifact Copier'
17-Jan-2010 05:14:21 Copying artifact Cargo Logs
17-Jan-2010 05:14:21 Finished copying artifact Cargo Logs in 0s
17-Jan-2010 05:14:21 Copying artifact Jira Logs
17-Jan-2010 05:14:21 Finished copying artifact Jira Logs in 0s
17-Jan-2010 05:14:21 Running post build plugin 'Clover Results Collector'
17-Jan-2010 05:14:21 Running post build plugin 'NCover Results Collector'
17-Jan-2010 05:14:21 Running post build plugin 'Maven2 Build Processor'
17-Jan-2010 05:14:21 Finalising the build...
17-Jan-2010 05:14:21 Stopping timer.
17-Jan-2010 05:14:21 Build JIRAFUNC-JDK16BATCH06-1430 completed.
17-Jan-2010 05:14:21 Running post build plugin on server 'Build Hanging Detection Configuration'
17-Jan-2010 05:14:21 Running post build plugin on server 'Clover Delta Calculator'
17-Jan-2010 05:14:21 Running post build plugin on server 'NCover Results Collector'
17-Jan-2010 05:14:21 Build has already been failed. Ignoring return code.
17-Jan-2010 05:14:21 Saving build results to disk...
17-Jan-2010 05:14:21 Generating build results summary...
17-Jan-2010 05:14:21 Indexing build results...
17-Jan-2010 05:14:21 Finished building JIRAFUNC-JDK16BATCH06-1430.
17-Jan-2010 18:43:30 Manual build triggered by bbaker
17-Jan-2010 18:43:34 Build JIRAFUNC-JDK16BATCH06-1431 started building on agent Elastic Agent on i-28380f40
17-Jan-2010 18:43:34 Running preRetrieveSourceCode task...
17-Jan-2010 18:43:34 Updating source code to revision: 105939
17-Jan-2010 18:43:34 Source found at '/mnt/bamboo-ebs/bamboo-agent/build-dir/JIRAFUNC-JDK16BATCH06'. Updating source...

when in fact the only lines here that belong to the new build is

17-Jan-2010 18:43:30 Manual build triggered by bbaker
17-Jan-2010 18:43:34 Build JIRAFUNC-JDK16BATCH06-1431 started building on agent Elastic Agent on i-28380f40
17-Jan-2010 18:43:34 Running preRetrieveSourceCode task...
17-Jan-2010 18:43:34 Updating source code to revision: 105939
17-Jan-2010 18:43:34 Source found at '/mnt/bamboo-ebs/bamboo-agent/build-dir/JIRAFUNC-JDK16BATCH06'. Updating source...

Bamboo should not show the old build logs. Its very confusing. If should at least put a marker (say 10 news lines and a message) to the new log so that a human can know what is old and what is new.