All other forms like kunena forum or comments in article works fine with smileys and BB code. I dont think that a plugin is the issue, or do you? I did aleady deactivate some plugs to try.
And if that would be a plug, why isnt that issue shown in Mozilla Firefox?
Please check FAQ Chapter 6.3.1, 6.3.2 and 6.3.3. There is a list of components that causes troubles with an explanation why. So it might be a 3rd party component or the template itself (you can switch to the default Joomla template temporally to see if it is the template).
uddeIM & uddePF Development
CB Language Workgroup
CB 3rd Party Developer