Sorry for taking long to reply. Attached please find images and modified dwg for your reference. I turn off the hatch and turn on the wall justification line display here for clarity. Note that in original files I received, not all the joints currently have wall merge applied (see NEW-FP-THIRD_turnOnJustificationDisplay.png)
This might be one reason why this joint appears to have a cleanup failure.
The joint here is a bit tricky because I cannot use Cleanup Radius adjustment alone to fix the Cleanup issue, so besides using wall merge the wall cleanup joint can be handled by editing justification, if keeping justification edge on specific side is not critical, I made an example in attached DWG. The upper right joint is done by using Edit Justification Line command (select a wall-->Right Click-->Edit Justification. Note that in ACA 2008 you will need to hold CTRL key while clicking the Edit Justification grip to keep the wall position from changing) .
Please let me know if this clarifies and let me know if there are other questions.
Thanks,
Sam