Issues with title style when using subtitle plugin

Hi, I’m not sure if this belongs here or on the plugin’s support forum, but I figured you all would help provide some insight into why this might be happening. I just downloaded this theme to give my blog a new look and I LOVE it. But I also recently downloaded the “Subtitle” plugin and using this theme with that plugin is causing the posts with subtitles to format incorrectly.

On some posts, the formatting of titles is totally screwed up (click for an example). Another post (which is scheduled) has extra dividing lines between the subtitle and date, and some of the lines appear slightly off-center (click for screencap).

Ideally, I’d like the format to have the title, subtitle, then the dividing line, followed by the date, but I can’t figure it out. As long as I can remove the extra lines and make sure that the subtitles (and dividing lines) appear centered in alignment with everything else, I’ll be happy.

I may cross post this to the plugin’s support page, but I hope you can help!