Version:            (using Devel)
Installed from:    Compiled sources
Compiler:          gcc 4.2.3 
OS:                Linux

Kopete seems to be escaping formatting within messages once too many times before being sent, and unescapes messages once too many times upon receipt.

Examples:
1) Kopete user sends bold text.  Pidgin renders such as unbolded "<b>text</b>" instead of rendering the formatting properly.  I traced the message in wireshark; "&lt;b&gt;" were sent in the message, instead of "<b>".

2) Pidgin sends Kopete plain text, with angle-brackets in it.  The Pidgin user types "I <3 Kopete", but Kopete parses it as an [invalid] tag, and renders only the "I".

3) Kopete user sends plain text with angle-brackets.  The Kopete user types ">_< the face", and Pidgin renders it properly.  Checking with wireshark shows that "&gt;_&lt;" were sent, which is the expected behavior.

All three scenarios were tested using both AIM and XMPP.