Are you on mobile?

Yes.

Well even on my phone its still messed up.

I opened the post in my browser, and the underline was only under the bold part. Let me try something: [u][b]Bold underlined.[/b] [i]Italics underlined.[/i] Underlined only.[/u] Yeah, you need to switch the [u] and [b] in front of the word bold. What happened was, you began a bold, then inside that bold, began an underline. The next thing you did was end the bold. This is invalid XML structure. You can't have an element open inside another element and close outside of it. When the browser reaches the end bold tag, and there hasn't been an end underline tag, it ends the underline automatically. I believe this is actually the correct behavior. Switching the open bold and underline tags fixes the problem, as now both the bold and italic elements are completely inside the underline element.