Hi,
upon request from Emacs developers, it is now configurable if org-mode fortifies the block delimiting lines #+begin... and #+end... up and including the final newline or not. This is something you will only notice when you have a font for this using a background color or an over/underline. This can cause problems with the Emacs display engine, apparently.
There is now a new variable `org-fontify-whole-block-delimiter-line', default is t. In the process I cleaned up the corresponding fontification function. Please report if with my recent commit any fontification issues or errors start to appear.
Thank you.
Carsten