If you see users in some channels, then you may just be joining channels that do not have any users. For example, even though #scripting may be on one network, it may not be on another network.
The other possibility is that you're trying to join a channel name that is in code page encoding. When you try to join the channel, you're using UTF-8 encoding. That means you actually join a different channel. There are many posts on this and as always, the recommendation is that any channel owners who have channel names using code page encoding should change to the same channel name in UTF-8 encoding. Such channels are easy to notice as they have accented characters, such as é, or non-English characters such as 日本語.
Try connecting on a major network (something like Efnet or Undernet) and joining a channel like #help. You should see people there. If you do not, then you have a problem that needs to be figured out. If you do, then it's probably one of the issues described above (neither of which is a bug, btw).