1) Create a SVN repository with the following history
Revison 2 is a copy from branch1 to branch 2:

1. svn cp -m '* break bamboo' file:///repo/branch1 file:///repo/branch2

------------------------------------------------------------------------
r2 | apache | 2010-03-01 18:25:36 +0100 (Mon, 01 Mar 2010) | 1 line
Changed paths:
A /branch2 (from /branch1:1)

• break bamboo
  ------------------------------------------------------------------------
  r1 | apache | 2010-03-01 18:25:06 +0100 (Mon, 01 Mar 2010) | 1 line
  Changed paths:
  A /branch1
  A /branch1/dir
  A /branch1/dir/file.txt

create structure
------------------------------------------------------------------------

2) Create a buildplan that checkes out the "/branch2/dir" SVN directory

3) Make 2 manual builds

4) Enjoy: Bamboo checks out revision 1 instead of 2
01-Mar-2010 18:27:21 Build DEMOHEAD-DEF-3 started building on agent Default Agent
01-Mar-2010 18:27:21 Running preRetrieveSourceCode task...
01-Mar-2010 18:27:21 Build always require a clean checkout
01-Mar-2010 18:27:21 Cleaning build directory '<STRIPPED>/bamboo/home/xml-data/build-dir/DEMOHEAD-DEF'
01-Mar-2010 18:27:21 Updating source code to revision: 1
01-Mar-2010 18:27:21 Working directory '<STRIPPED>/bamboo/home/xml-data/build-dir/DEMOHEAD-DEF' is empty. Checking out SVN URL 'file:///<STRIPPED>/branch2/dir'
01-Mar-2010 18:27:22 Error occurred while executing the build for DEMOHEAD-DEF-3 : Failed to checkout source code to revision '1' for <STRIPPED>/branch2/dir

NOTE: Failed build number is "3" because of Bamboo runs manual builds twice sometimes. Build 1 and 2 were both triggered by the initial build and are based on rev 2. All future manual builds fail during the checkout phase and are based on rev 1. Commiting a change beneath the "/branch2/dir" directory fixes the buildplan.