Well, it isn't incopetence, but it isn't a bug, either. It is just the way BB code works, which is stupid.
The Rich Text Editor doesn't always lay things out correctly. As soon as you start adding in different fonts and centering to your text, the rich text editor will occasionally lay down the brackets incorrectly. And then things look like what you have above. You'll notice it laid it out as :
(color)(u)(b)(font)(color) Your Text (/font)(/b)(/u)
On the very first line where things start going weird. To line things up, you need the brackets to always open and close in order, with no hanging code. Aka, you need (u)(b)(font)(color) Your Text (/color)(/font)(/b)(/u), or the equivalent.
As soon as the rich text editor started getting things misalligned, and then you added in more colors afterwords, the bb code editor was desperately trying to figure out what the rich text editor was telling it. And, therefore, you get junk!
Your best bet, when you start wanting to stack different types of formatting, and turning them on and off at various points, is to do it manually, and make sure things open and close in the correct order. X.X