DesignMerge allows you to merge Tagged Text into a variable text link. The variable link will translate the tags that are in the imported data. This allows you to embed styling information in the data to override the styling that has been applied to a variable text link in the document. Tags can describe almost anything, including paragraph-level attributes, character-level attributes, and special characters. If a variable text link is not merging tagged text as expected, then confirm the following:

First, confirm that you have set up the variable link to use the appropriate Filter. For more information about this variable link setting, see DesignMerge Documentation. 

Next, please note that several tagged text import filters use the Less Than (<) and Greater Than (>) characters as reserved characters. Therefore, these characters must not be used in the name of a paragraph style, character style, or color swatch that is applied to a variable text link which will be merging data in a tagged text format. Otherwise, a conflict will occur when the text link merges the tagged text.

Confirm the tags have been entered correctly in the data. Check the syntax and spelling of the tags. Also, confirm a sufficient number and the appropriate type of tags have been included. The data may require additional tags to achieve desired formatting results. Otherwise, a conflict or unexpected formatting will occur when the text link merges the tagged text. 

Also, check to see which paragraph style is your document's default paragraph style and also which character style is your document's default character style. These document default styles are the styles that will be applied, for example, when the data includes a tag that ends the application of the previously applied style. To see which styles are your document's default styles, follow the steps below:

1. Open the document.
2. Deselect all content/objects (click with the Selection tool on empty space, for example, on the pasteboard).
3. Open the Paragraph Styles panel. Confirm the currently selected style is the style you prefer for the default. If not, click on the name of your preferred paragraph style to make it the document's default paragraph style and save the document. 
4. Open the Character Styles palette. Confirm the currently selected style is the style you prefer for the default. If not, click on the name of your preferred character style to make it the document's default character style and save the document. 
5. To confirm you have now set your preferred styles for the document's default styles, create a new text box in the document and enter some text. Highlight this text and confirm which styles have been automatically assigned.

For more information about MPS Tags, see the How to use MPS Tags to style variable data knowledgebase article.

For more information about merging tagged text, see DesignMerge Documentation.