The symbols < and > have special significance in HTML: they indicate the beginning and ending of a tag. Therefore you cannot use these characters in the content of a HTML file. If you want to use any of these characters in your content, you need to use the HTML encoding: < and >. Luckily, RoboHelp automatically uses this encoding when you type any of these characters.
The answer is: There is no way to use those symbols themselves. Just adding those symbols as text will upset your browser. That the browser doesn't translate the encoded characters in the title back to the original character, it is a bug in the browser.
Most special characters don't need encoding. You can use encoding for characters such as ë but that mostly not necessary. Characters with special significance are: <, >, &, ' and ".
Willam is correct that you cannot type < or > directly into the HTML code and in pointing out that RoboHelp automatically converts the code when you type that in design view.
However, I think that you are aware of that and it is not the problem you want addressed. You can see that you can type that straight into the Topic Heading but your Topic Headings are not typed in, you are using fields and what you are finding is that if the Topic Title contains the brackets, that works everywhere other than Topic Headings. Is that correct?
If so the cause is linked to what Willam has pointed out but I am sure Adobe could work out a solution. Report it as a bug. Please follow this link.
See www.grainge.org for RoboHelp and Authoring tips