HTML/CSS not allowed in "text change" section of Ultimate Branding plugin?

I wanted to replace some text site-wide, and I've been using Ultimate Branding "text change" for that. I just tried to add a paragraph and bold, and it's adding some weird code.

So, for example, I replace some text with:
bla bla bla <p>this is some more text<p>

On the page, it comes up with:

bla bla bla

this is some more text </p>

With the closing paragraph & strong tags visible (and an extra slash, for some reason). Any thoughts on why? (It DOES add the paragraph and bold, however)