For Gawds sake, do not use the </> code insertion tool for entering regular text!
Pages expects every font family member used in it to be a physically installed font. Although you can make a font in Word that has no family member installed, appear as a faux italic or bold, Pages will automatically perform a font replacement when it encounters these faux font references. Typically, that replacement will be to Times or Times New Roman and the font size may not match. Pages will display a warning panel on these font replacements.
The simplest approach is to select the replaced font text, and change that font and font size to the current font and size used elsewhere in your Pages document. The Word document during the Pages translation process remains read-only and you cannot fix it in Pages.