The "Integrate Branch" action is selectable per run. Let's say I have two runs, #2 @57 and #1 @45. You can select a previous run, not necessarily the latest/@HEAD.

If I select #1, and then click "Integrate Branch" action, the message that is displayed before "Integrate this build to upstream" button is clicked shows correct SVN revision of run #1 @45.

However when the plugin operates, it does not merge from revision of #1 as selected. Instead, it merges to upstream from HEAD of branch.

Here is my log. As you can see, I tried to integrate @45, as evident from message, however the plugin operated on @57:

This will merge http://svn/branches/feature (rev.45) to trunk-build

Last Failure
Switching to the upstream (http://svn/trunk)
U         New Text Document.txt
 U        .
At revision 57
Merging http://svn/branches/feature (rev.57) to the upstream
C         New Text Document.txt
 U        .
Found conflict with the upstream. Reverting this failed merge
Switching back to the branch (http://svn/branches/feature@57)
U         New Text Document.txt
 U        .
At revision 57
Conflict found. Please sync with the upstream to resolve this error.
Completed

If the plugin always integrates from @HEAD of branch, then the "Integrate Branch" action should be moved from per-run-level to job-level, and the message should be fixed