Import overlaying text and additional categories

I import events from a google calendar. I am adding text, featured image, and an additional category (original plus an additional one is checked) after this is imported.

I have the following setting checked: Preserve the most recent change in each event field, whether that change occurred on my site or at the original source.

Each time the import runs it overlays the text and additional event category. I thought selecting this option in the settings would prevent this.