RSS Multi Importer – posts automatically duplicating

I’m on version 3.13 of the plugin, and version 3.9.2 of WordPress.

I’m seeings my posts automatically duplicating and triplicating. I’ve read through a similar issue regarding these duplicate posts, and it sounds like one possible cause is a slow server. I’m using a shared server, and Siteground is the host. If I contact my host, is there some quantitative spec that I could pass along as being an acceptable server speed for this plugin? Are shared servers generally too slow for this plugin?

Thanks in advance.

https://www.ads-software.com/plugins/wp-rss-multi-importer/