Also FYI, I just downgraded to bbPress 2.3.2 and everything works great. Seems to be some kind of issue with 2.4.
I have the exact same problem – WP 3.6.1, bbPress 2.4. Any edit or reply to topic loads the whole post html into the window. Also have tried deactivating all other plugins etc. with no results.
Can anyone help us with this issue? Pretty frustrated at this point..