Issues for large (many channels) bots

Question then: Why when I logon through an external IRC client, I can see all the viewers in the chat channel, but in the Web Browser API chat the count is different?

I only see a few of those users. Even waiting 5 minutes and refreshing the list in web browser does not show the total number of users that are in the IRC channel. Does not matter how long I wait, The IRC user count is a lot higher than what is shown in the chat list, and the count in IRC is close to viewer count.