In mm_tree_block by default, bid 2 is associated with mmtid 11, which is the Upper left picture "default-image" node. However, bid 2 is Text for right column, while bid 3 is Upper left picture. I've attached a patch to the install file that replaces bid 2 with bid 3 in mm_tree_block.
The behavior I was noticing that led me to make this change is that I'd enabled the Text for right column block for one of our themes, but not the Upper left image block. In the region where TFRC was enabled there was then a link to the "default-image" page at the site root, which would have allowed people to add right column content to it. Making this change requires users to create a page with TFRC set in menu appearance before they see the edit link and ensures that the edit link goes to the TFRC page they created.