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I'm not clear if you were viewing the PDF in Inkscape or somewhere else. But my best guess is that you used Flowed Text, which really only works properly (a) inside Inkscape and (b) in SVG files. If you dragged out a text box with the Text tool, and then typed in the text, you created Flowed Text. If you don't remember, just select the text in the SVG file, and look at the status bar. If you used flowed text, it will say so. I'm not sure if it will be identified in the PDF
There are a couple of fixes for that. 1 - Convert to regular text, via Text menu (might have to reformat the text); or 2 - Convert to paths, via Path menu > Object to Path.
If the PDF will be viewed on different computers besides yours, you'll probably want to convert to paths. That's because if someone on a different computer opens the PDF, and they don't happen to have that font installed, they won't see it correctly. So converting the text to path will make sure that everyone sees it like you meant it.
However, once you convert it to paths, you won't be able to edit as text anymore. So be sure you have the text exactly as you want before changing to paths. And....well in this case, it's probably not a big deal. But if it were a lot of text, you might want to save the text, as text, somewhere in the file, in case of future edits.
If none of that works, or seems to fit, would you be able to share the SVG file with us? Then we can investigate better.