This is probably caused by html markup in the titles themselves.
Do you have this online so I can take a look?

Is is a bit hard to see what is going on, because Easyblog doesn't just render the page in normal HTML. It pushes it all through a json object script.

But in there, I see that there are actual <br> tags inside the headings of your page. So to fix this, you need to remove those from the heading tags.

If it is Easyblog that is placing these <br> tags inside the headings, then you need to ask Easyblog for a fix.

See the settings, you can give it an "Index Title":
docs3.regularlabs.com/quickindex/getting-started/configuration

Quick Index doesn't specifically cache the results. So whether or not the output of your page is cached, depends on the cache settings on your setup.

Read for more on caching here: www.joomlabeginner.com/blog/tutorials/81...able-cache-in-joomla