Bug reports are not currently being accepted through the SourceForge ticketing tools. The shell is being maintained by various (entirely self-appointed) subscribers to the mailing list,
so mail about any issues (bug reports, suggestions, complaints...) related to the development of the shell should be sent there. If you want someone to mail you directly, say so. Most patches to zsh appear there first.
Please note when reporting bugs that many exist only on certain architectures, which the developers may not have access to. In this case debugging information, as detailed as possible, is particularly welcome.