Recent Posts Thumbnails plugin causing spacing issues

I have placed the YD Recent Posts Thumbnails plugin in the sidebar of my blog, One Million Hit Wonder.

For some reason, the spacing between the Title of the Widget (“Latest News”), and the rest of the widget’s content, is huge! It varies depending on which page you are on – see this page for the most extreme example – https://onemillionhitwonder.com/advertise

Any ideas why this might be occurring?