I've noticed 2 things:
1) If you use shortcuts for bold text for example; ctrl + b it will do this without actually make it bold.
2) Using any unicode in your "reason for editing: makes you unable to edit the thread, page keeps loading
Tried it with this:
ư͗̑ͯͣ̿̋҉̠̟̭͖̣̮͈͖͈̬͇s͙̫͉͉̤̪͇͎̗̺͚̥̜̞̖̤͓̦ͨͧ̈́ͬ̀̀e̲̮̗̗̦̺͔̭͕̖̲̥̥̋̆ͨͤͬͪ͌̑̂̀̏͒̎ͥͥͤ͟ͅ ̡̛̭̫͖͎̼͕͔̖̙͔̠̥͖̘͋̌̉ͨ̓͐̓ͨ̇̚͘͡t̥͇͔̣͎̺͈͙͉̗̞̰̯̣̝ͨͤͨ͌́͘͠h̡͗ͣ͗ͫ̀͛ͦ͝҉̢͎̙̯̮̝̝̦e̿ͪ͊ͫ̔͐ͩ́̚ ̯̖̜̭̗͚̹͔̙̠̤͍̱̼̘͓̒̊͢͠ͅͅ ͉̞̘͉͉͎̪͉̻̥̺̙̝̘̗͖͂̆͐̇͋̚̕͟͟͟ͅs̵̨̩͍͉̖̝̥̮̹̭̗ͣͯ̀̇̚͢ĕͪ̌ͪͤ̏ͩͨ̄̇̋͛̎ͣͨ̑҉̷̢̳̫̻͇̬͙̩̦̣̭̠͟͡ͅ ͓a̵̶̷̫̠͖̙̝̩̹̲̖̱̹̜͉͋ͯ̋ͦͭ͆ͥ͑ͤ̊̓̽̍̿̍̌̿͝r̸̬̖͙͙̳̹̖̗͓̈̔̇͆͑̄̔͘͟͟ç̷̴̫͙͖͔̱͓̦ͨ̾ͨͯͫ͋́̏͐̚͟ͅ ̤̻̩͖͇̱̫h̷̶̡ͭ̇̐̎̍̀͒͐ͫ͒̽̽͏̪̝͎͎̱̥͉̺̯̦̟̲̩̼̣̖̞̞͜ ̍ͪ̈̃̽ͧ̏̇̆̿̉̿̓̍͏̵̕҉̮̟̰̖͓̼̠̖̫̩͉̮̞b̝̗̙͕̗̣̲͉̗̰̱̦̥̳ͤ̔ͯͪͣ̓̍͗̆̎̑͋̊̊̀͟͝͡ū̄̓ͮͥͦ̌́͏̧̛̬͎̠̖ ť̡̮̬̙̝̥͈́͒ͯ̏̚t̸̞͙͙͖̥̤̼̥̰̥̩̻͊̈́̌ͯ̒ͦͪ̑́͢͝ơ̔͆̾̄̋͂̐ͪ̐̂̌͗ͥ̓̎̋͋̈́̃҉̭̦̜̱͓͓̮̖͔̭̗̖nͬ̃ͬ͌͋͟ ̼̰͙̯̙̰͈̻̼͓̯̰͖͝,͕̗̤̘͎̟̳̫̩͍͓̰͕̦̣̻̃̑͊ͨ̽̌͊̄͑̈̑͡ͅ ̛̈́̿͋͊͐̓̅̊ͪ͏̛̖̬̤̟̩̮̕p̢̡̢̬̜̫̦̱͍͖̺̠͎̙͙͉̿ͯͦ́ͬ̈ͬ̽̿̉̽̋͑͒͑̌̀͠l̐ͤ̆̌̍̀̈́̋ͪ̾̃͋ͧͣ҉҉̗̲͕̻̦̺e͒̓ ̵̷̻̻̯̯̖̝̳͓̰͈̻͍̂̇̽̕ą̛͈̦̗̦͍̹̫͙̯͈̖̘̔̎̉ͮͥ͊͟ş̢͎̞̰̪͐̽̑̅̍̏̽͑̇͋̉͗͌͋͋̓̇̑͡e̍͆͛̍ͯ̑̒ͣ͑ͫ͂̔ͮ ̡͉͕̟͉͕̺̰̠̤̱̰̱̼̯͓ͪͅ