There is currently with an issue with the userlist not populating on many channels. This typically happens during events when the chat server is under heavy load. Also, related to this issue, moderator status may not displaying properly as well preventing mods from seeing the timeout and ban options in the web chat. Twitch is aware of the issue but there is not user end solution at this time.
If you are a mod in a channel, the chat commands will still work for moderation. These commands are:
/slow & /slowoff
Don't type the [ ].
You can also confirm you are a mod by typing "/mods" and make sure you are on the list.
IRC users will also experience userlist issues as well.