I can confirm bugs in RTE in both RC2 and RC3. I've got a chance to use ffox 3.6 with both flavors. They screw formatting constantly and the description made here or on the other topic mentioned are consistent with my observations.
More than that, it seems to me that there are some problems with bold, italics, underline. They are visually enabled only after I start typing the text, but not right after clicking on that icon or pressing the shortcut (ctrl-b, ctrl-i, ctrl-u). And if one tries to paste formatted text into quotes: good luck! The only workaround for me is copy text, paste in notepad, copy again, paste in SMF, reformat as needed. Plus, sometimes even if I'm editing my very own and original text, it screws up if there are multiple brackets involved, but I cannot describe a pattern.