Why does placing plain text override font color from master?

I am placing a plain text (txt) file into a text area that has no character style and a specific paragraph style. When the text is placed, the text takes on the paragraph style with overriden font color and size. When you hover over the style it has a plus after the name of the style. I can clear the overrides, but I am trying to figure out why it is happening and how to prevent it. They are just simple txt files with no styles or formatting in the original document. I know that import filters for other types such as Word will maintain styles and potentially local formatting, but this file is just plain text. Anyone have an idea what is happening and how to prevent it when placing plain text files? Thanks.