Version: (using KDE 4.0.83)
Installed from: Ubuntu Packages
If the pointer hovers the bat emoticon (:-[), in the "add emoticon" menu of the chat window, and then passes over another icon, the preview panel, on the right side, shows the latter and part of the wings of the former.
Same on KDE 4.1 RC 1
confirming as well KDE 4.0.99 Suse 11
Same here with Kopete 0.50.80 from Kubuntu packages.
Fixed for KDE 4.2 (r857734) and KDE 4.1.2 (r857736).