In the attached example, a preserve block, with before_after => "after" does not properly check whether the blocked text exists, and will add it multiple times.
e.g. first run the method set_up_tree (convergent), so prep the file, then switch to set_up_tree_recipe (non-convergent)
I would like some help in turning this into an acceptance test, and will happily fix the bug when I have some concentration time.
This could be related to other reported bugs about end-of-region (speculation)